Playing

Professions: which ones to combine

Gathering or crafting, the bonuses each profession gives at level 80 and the pairs that work best for each style of play.

Every character can learn two primary professions plus the secondary ones (Cooking, First Aid and Fishing) at the same time. Choosing well gives you gold while leveling and small but noticeable bonuses at level 80. You can browse every recipe in the Wiki.

Gathering or crafting?

Gathering (Herbalism, Mining, Skinning) gives gold from the first minute: sell what you collect at the auction house. Bots buy and sell there, so there is always a market.
Crafting (Alchemy, Blacksmithing, Enchanting, Engineering, Inscription, Jewelcrafting, Leatherworking, Tailoring) costs gold while you level it, but pays off with gear, consumables and level-80 bonuses.

A common plan: level with two gathering professions to save gold, and switch one of them for a crafting profession once you are close to the maximum level.

Level-80 bonuses

Profession	What it gives you
Alchemy	Longer-lasting elixirs and flasks, and better potions for yourself.
Blacksmithing	Extra sockets on your bracers and gloves.
Enchanting	Enchant your own rings.
Engineering	Tinkers for gloves, belt and cloak, plus gadgets and mounts.
Inscription	Exclusive shoulder enchants; glyphs to sell.
Jewelcrafting	Exclusive gems, much stronger than the normal ones.
Leatherworking	Exclusive bracer enchants.
Tailoring	Exclusive cloak embroideries; bags to sell.
Herbalism	A heal over time you can use in combat.
Mining	Extra stamina.
Skinning	Extra critical strike.

At level 80, the crafting bonuses are similar in size, so the choice is more about comfort and gold than about raw power.

Pairs that work well

Natural pairs (one gathers for the other)

Mining + Blacksmithing: plate wearers, especially tanks.
Mining + Jewelcrafting: any class; gems sell well.
Mining + Engineering: very fun, plenty of gadgets; great for PvP.
Herbalism + Alchemy: self-sufficient raider; flasks and potions for free.
Herbalism + Inscription: steady income from glyphs.
Skinning + Leatherworking: leather and mail wearers.

Independent pairs

Tailoring + Enchanting: cloth wearers; disenchant what you make or find.
Herbalism + Mining: the classic pair for making gold while leveling.

By style of play

Leveling a first character: two gathering professions. You will have gold for your mount and training.
Raiding: any crafting profession that gives a bonus, ideally one that also makes your consumables (Alchemy) or gems (Jewelcrafting).
PvP: Engineering is the most versatile thanks to its gadgets.
Making gold: Inscription, Jewelcrafting and the gathering professions sell constantly.

Don't forget the secondary professions

Cooking gives buff food for raids, First Aid heals you between fights without spending mana, and Fishing feeds your Cooking. They don't use one of your two primary slots, so it is worth leveling them along the way.