whenever garret talks about his motivation he always talks about "paying rent" and of course this seems like a reasonable thing to steal for but garret is a "master thief" (master my ass dude every guard knows what your face looks like) and should reasonably be making enough money to lay pretty low for a while if hes spending his money like is shown in game.
it seems kind of presumptuous of me to assume that but looking at the economy of thief im pretty sure garret should be rich as hell especially after three games and probably something like a decade of freelance thieving and its not like he lives in a new york penthouse
my biggest two pieces of evidence towards garrets cost of living being far lower than his pay rate are in thief three.
firstly if you sneak into your landlords apartment you find like.... a total of 400 gold i think if you count the arrows you find in his chest. his landlord is also being blackmailed and says that his payments of 50 gold are really draining his pockets dry in a diary entry.
you need to keep in mind that there are two other tenants shown in game who arent garret so thats at least three people paying him per month (id also like to add that garret isnt afraid of stealing shit from his landlord so its not like hes actually losing money from rent)
secondly a lot of the the rare loot in the game usually costs somewhere around 150 gold. at one point you find a mans life savings (which is supposedly the sole factor in deciding if his widowing wife will be able to afford to live even though she lives in a mansion already filled with expensive shit) which only adds up to 500 gold.
for context if you are playing on hard like i do you are usually expected to make at least 2000 gold per level. i think throughout all the games my garret probably made about 50.000 gold so far
so the question remains where the hell is he spending all this money? he could easily be paying for all the basic costs of living given the evidence. whats he so ashamed of that hes not telling us about?