My advice is to judge the wealth of your character not by a number but by what kind of lifestyle you believe they could reasonably afford. So for example, if you're roleplaying a deadbeat smuggler on the run from a loan shark you're probably not going to afford a luxury suite on Naboo. But if you were a renowned entrepreneur you'd probably be able to buy the hotel it's in.
So yeah, people don't keep track of how many credits one has but sometimes sellers will deny a purchase in the marketplace if they believe your character cannot reasonably afford it.
Of course; if you wanted to you could keep track but don't expect too many people to honour it if they don't.