Heya,
Depends how much disposable income you have really and what your priorities are.
I budget the same for everything. I either trade out things to generate capital (such as selling equipment to get different equipment). Or I just save here and there when I have money that isn't needed and I drop it in an account just for hobby spending. A basic sum of cash that I can play with and not feel guilty about spending, if there are not other more important things first.
I do this basically:
1. I pay myself first, so I put away 15% of everything I make to retirement funds. I do this before everything, even bills.
2. I pay my cost of living for my family. I do not keep debt. We budget our cost of living and try to stick to it.
3. I pay for any debt items (vehicles, etc) that are monthly that cannot be fully paid at the time.
4. I maintain enough accessible cash to cover our cost of living and expenses for up to 6 months in case unfortunate things were to happen.
5. I maintain a small "what if" cache that I keep skinny.
6. I have a hobby cache, and that's where I just dump excess stuff after I've satisfied the above and after my family's needs or wants are met (ie my wife & daughter).
I do this because my toys cost a lot more than my wife/daughter's do, and I'm the sole income in my family. So they are taken care of before my hobbies are.
I generally set a goal or set of goals for different hobbies, and I just shop, or wait, and keep eyes out for deals, or save towards a goal. I don't impulse buy unless it's really inexpensive (ie, under $100 or something). If I'm after a $2,000 lens, I just set a goal, budget for it slowly, shop for deals, trade out equipment I don't want/need, and when it's time, I earn the goal. I don't just buy what I want immediately and make payments. It's a hobby, not my business.
Very best,