One of my expensive hobbies is woodworking. Every month I'd like to say I put away $100 of my paycheck to go towards woodworking. Every paycheck it adds onto a budget pool. If I want to buy a new tool, I can check how much I've "saved" since my last hobby purchase and determine if I can buy it or maybe I decide I want a smaller tool first.
This would help me from over spending on a hobby. The current spending plan doesn't seem to help with this as it would just say "don't spend over $200 a month on it" and some months I would spend close to $0. If I want a $1000 tool, it will take months to save for it but in the meantime I want other hobby purchases to affect how much I'm saving towards that tool.
I think sometimes this is considered bucket budgeting? Id also think you could allow it to go negative. If I decide to make a purchase greater than my spending pool has, then it should become negative showing me I need to save for longer to get back to a point where I can spend money on it again.