I've been helping a group of friends understand their finances and had to lead a budgeting discussion last night...
MPP: We don't budget, we just spend as little as practical, earn more than we spend and invest the surplus... So we had to invent a budget. I named it our "fudget".
Similar to your problem:
A friend asked me how much my budget was for a trip I was gonna take, as it was a long trip to an expensive country and she knows I'm cheap/frugal/good with money (depending on your definition). I had to admit I had no budget.. I always check what price levels I can expect and have a maximum number in my head, but in the end I'm always way, way under that 'budget'.
I have never understood all that budget stuff.
I have my "stone set" expenses like rent and electricity. It is the same, every single month, it may only change once a year. You don't need a budget, because you cannot increase this (not without knowing it very well).
After that I buy food. I don't have a budget here. I just buy what I need and want to eat, and no budget is changing that. I surely am not gonna starve.
Eating out? I'm not a fan of this anyway. If it happens, it happens. No budget is making me say "Ah, no, I can't come to your birthday" (or whatever event there is).
Anything else? I am too much a perfectionst (hm... I admit so far it does not sound like it :D) to buy stuff I have not informed myself before, often extensivly.
I am not going through this hassle if I don't need X.
The only thing I spend money without thinking about it (or it being a regular necessity) is books.
And even with all the time of the day and the most ferocious reader, you can only buy so much books. (Of course I still have an unread books pile. But then again, the bigger it gets, the less inclined I am to buy new books, so it evens out eventually.)