Terraria has no formal player class or leveling system. However, weapons can be grouped into four distinct categories based on their damage type – melee, ranged, magic, and summoning. Each class has its strengths and weaknesses and has a wide variety of weapons to choose from.
The melee class sports high defense and decent crowd control, but many melee weapons have a short attack range, and those that are viable at a distance tend to do lower damage than their close-range counterparts. Melee weapons include swords, spears, and yoyos. Melee hybridizes well with summoning since summons gain armor penetration as long as a Sharpened buff is active while a melee weapon is held, and melee speed bonuses also improve the speed of whips.
Rangers are able to attack from a distance, doing high single-target, piercing, or splash damage. They utilize weapons like bows and guns, as well as thrown objects. Ranged users must constantly acquire ammunition, unless using the Endless Quiver or Endless Musket Pouch or using a ranged weapon that doesn't require ammunition such as the Toxikarp.
Mages are fragile but highly varied in attack style, often utilizing special mechanics such as homing, lifesteal, and area-of-effect damage. They are held back by reliance on mana, which regenerates very slowly unless the Mana Regeneration buff is in effect. Magic users can often sustain their mana using Mana Stars when fighting many enemies at once, but must craft or purchase mana potions if they wish to recover mana instantly during boss fights. Magic hybridizes well with summoning since whips can be used as side weapons while mana regenerates, and the presence of minions ensures that hybrid mages will never be defenseless.
Summoners deal most of their damage using autonomous minions and/or sentries, and their attacks usually have excellent accuracy. However, most summoning armor sets have low defense in exchange for their high damage potential. Whips are primary weapons that focus summons and increase their damage. While many players do challenges where only summon damage is allowed (Whips, Summon weapons and Mounts), the Summoning class was balanced around the idea of the player also using the strongest normal weapon available to them in addition to minions and whips. 
Each class gains more complex abilities as the game progresses, enabling more strategic variety in combat. It is advised for players to try out every weapon they find to help determine what works best for them. It is also recommended to use buff potions and healing potions to increase efficiency and survivability in combat (especially during events and boss fights).
In general, it is recommended to focus on one class. Equipment slots are limited, and many armors and accessories only benefit a specific class, especially later into the game. Summoners are an exception to this rule, since summons can deal damage alongside melee/ranged/magic weapons, so summoning gear will always provide a benefit as long as summons are being used. All classes can use at least two minions at all times even without using summoning gear (by using a Bewitching Table), so it's recommended to always utilize these free slots regardless of primary class.
Even when not specifically using a hybrid set, backup weapons from another class can be helpful should the situation require a different weapon. For example, Giant Cursed Skulls might pose a threat to non-summoners, but a whip such as Durendal can kill them easily even without summon damage boosts.
Prior to encountering a boss, set bonuses from wooden and ore armor will almost exclusively provide additional defense, and accessories will not discriminate by weapon type when giving bonuses. When combined with the general scarcity of weapons and the need to survive, there is little point to sticking to a "class" this early on. For these reasons, players are recommended to make use of whatever they can get their hands on. Players can acquire a gun or magic weapon early on by smashing one of the Corruption Orbs (in Corruption worlds) or the Crimson Hearts (in Crimson worlds).
Gold BroadswordPlatinum BroadswordMandible BladeKatanaIce BladeEnchanted SwordTerragrimBone SwordGladiusBladed Glove (during Halloween)Bloody Machete (during Halloween)Candy Cane Sword (during Christmas)Fruitcake Chakram (during Christmas)StarfuryFalcon BladeLight's BaneBlood ButchererBlade of GrassTentacle SpikeRallyMalaiseArteryAmazonStorm SpearThe Rotted ForkEnchanted BoomerangShroomerangIce BoomerangTrimarangThorn ChakramFlaming MaceBall O' Hurt()
While certain weapons, such as the Blade of Grass, are technically available to the player before fighting a boss, they are difficult to acquire without other post-boss equipment.
With a bit of luck, Fossil Armor can be obtained early on and without much difficulty.
Mages must increase their mana capacity through the use of Mana Crystals before magic weapons become viable. The Magic Hat and Wizard Hat will provide a set bonus when used in conjunction with any robe. Jungle armor and Ancient Cobalt armor can be used interchangeably, with each piece providing the same benefits, and the set bonus being given even when a mix of the 2 armors is used. Depending on the player's skill level, the Demon Scythe can technically be obtained at any point in the game, as Demons will always naturally spawn in the Underworld.
Pre-Wall of Flesh
Once you start defeating the first bosses new options become available. In addition, you should have enough mana to use magic weapons. However, the armors still only give small bonuses, so you can still safely mix class styles without a significant loss of damage.
Dedicated summoners are still rather weak at this point, although their summoning items can be used by any class.
On the Desktop version, Console version, and Mobile version, with the changes to Obsidian armor and the addition of Spinal Tap, Summoners become much more powerful at this point than in previous versions of the game.
Bee armor is preferable if you are planning to use your minions more often and would like to play a more passive role focusing on dodging more than attacking yourself, but Obsidian armor (on Desktop version, Console version, and Mobile version) trades 1 of your minions for +20% additional summon damage and +30% whip range and +15% speed.
Shield of CthulhuWorm ScarfBrain of ConfusionHive PackBone GloveBone HelmFledgling WingsCloud in a BalloonBlue Horseshoe BalloonYellow Horseshoe BalloonPink Horseshoe BalloonGreen Horseshoe BalloonBundle of BalloonsBundle of Horseshoe BalloonsLightning BootsFrostspark BootsTerraspark BootsAmphibian BootsBand of RegenerationObsidian ShieldStinger NecklaceShark Tooth Necklace
At this point in time, it becomes almost mandatory to pick a specific class. Many accessories will only benefit a certain class, and armor sets start to benefit only certain types of damage. However, summoner hybridization remains not only viable, but extremely potent due to the availability of the powerful Sanguine Staff.
At this point, you may also want to start working on getting good modifiers for your equipment.
- Despite being a Pre-Hardmode sword, it can still be reliable in many early Hardmode scenarios, especially if paired with a Power Glove.
For the mechanical bosses you have a choice between two whip-summon combinations. The Firecracker pairs well with the Sanguine Staff due to it's high base damage getting increased with the Firecracker's debuff that increases summon damage by 2.75x. The Blade Staff pairs well with whip stacking the Cool Whip, Durendal (After one Mechanical Boss), Spinal Tap & Snapthorn to the Blade Staff's low damage highly benefitting from the tag damage that the mentioned whips inflict.
This is the point where a mixed class becomes rather weak compared to a single class, mainly due to there being separate armor sets for each class. You can of course still play a mixed class, though it is recommended to have a backup armor set (e.g. in the vanity slots) so you can switch quickly for some additional damage or defense. Hallowed armor may be preferred for extra survivability. At this point buffs are extremely useful for bosses and almost necessary in master mode.
The Tavernkeep's armors provide minion and sentry bonuses while also providing significant melee, ranged, and magic bonuses. Hybridization is required to bring out their full potential. When using the Blade Staff, be sure to use Durendal, Snapthorn, Spinal Tap and Flask of Ichor for best efficiency.
With the Hardmode Dungeon and the Pumpkin Moon now available, players have access to a variety of new equipment. Furthermore, any Biome Keys you have obtained are now usable. You could attempt to skip this stage by killing the Empress of Light or summoning the Frost Moon, but most players won't be able to defeat either of them until they've progressed a bit further.
Both sets of Beetle are viable for different situations. However, the offensive variant is not optimal when using weapons that have their DPS unaffected by melee speed, such as Vampire Knives.
Both the Spectre Mask and Spectre Hood are useful for offense and defense, respectively. The listed hybrid set is strong both offensively and defensively, but is harder to obtain.
- While the Terraprisma is an incredibly powerful weapon, it is also extraordinarily difficult to obtain. It requires you to defeat the Empress of Light during the daytime which is able to kill the player in one hit regardless of equipment that provide defense or dodging effects such as Holy Protection. For strategies on how to fight the enraged Empress of Light, see Guide:Obtaining a Terraprisma.
- The head and leg slots of Valhalla Knight armor can be swapped for pieces that provide minion capacity, while still retaining the breastplate's high health regeneration.
At this point you can start using mixed class setups again, since you can kill everything easily. (except when fighting the Moon Lord).
For Moon Lord and endgame there are once again two whip-summon combinations. The Stardust Dragon Staff benefits greatly from the Firecracker due to its high base damage and Firecracker multiplying it. But due to the Firecracker's range, it requires you to get close to enemies and bosses. The Terraprisma benefits from the Kaleidoscope due to its low damage benefitting from the high tag damage from the Kaleidoscope. But due to the obtainability of the summon, it requires you to fight the Empress of Light during daytime which is an insta-kill boss, it is seen as one of the hardest bosses in the game. Note that a Dark Harvest should be used as a secondary whip in both combinations to provide a whip speed buff for the primary whip.
These setups sacrifice part of their own damage to make boss fights smoother for the entire team. A tank keeping bosses in one place should, depending on your group size, result in the overall party's DPS being higher, due to less deaths, ease of aiming, and no situations where one player runs away with the boss while everyone else chases them. The healer helps increase survivability for their team, but sacrifices large amount of their own damage and defense.
- If using Valhalla Knight armor, use Minishark (with no speed modifier) with Exploding Bullet to damage yourself and activate Ballista Panic, Brain of Confusion, Master Ninja Gear, and Star Veil as often as possible.
- In 1.4, Brain of Confusion provides a 17% dodge chance, and should be used over Master Ninja Gear if the dash effect isn't desired.
- During boss fights, the Paladin's Shield (or its upgrades) should be given to another player to further increase your survivability. Keep in mind that wearing the shield yourself will prevent you from receiving its effect from others.
- In 1.4, Putrid Scent, and its upgrades, is the corruption equivalent of the flesh knuckles and is used to reduce aggro.
Some equipment sets are not meant for fighting, but for other activities, such as fishing, building and exploring. All equipment is optional and makes it easier to perform the task, but otherwise simply use what is at hand.
Summoner gear might prove useful to defend against enemies while engineering.
Summoner gear is useful for defending against enemies while building.