I don't think you even need multiple thieves to keep your gears updated. With 2 level 8 thieveries (Buy glove and belt from stores with a unique Fin top somewhere from act 1, probably seeker camp store) and stealing twice from nearly every NPC in the game that has money on them (Which include random npc like some dude standing by the dock and he has trader gold on him for some reason) I left Act 2 with updated divine gears and 300k, way too much money tbh and makes me believe 2 thieves are already overkill.

1 Lucky charm + 1 Barter + 1 Thievery should cover the money and gear issue with no need for a respec. You don't even need Barter maxed, level 2 or 3 is more than good enough and just boost their attitude so you can get around 15-20% discount /extra price, more if you have barter gears every time you shop which really adds up.