When I was first starting out, and every time I get a new job/raise, I do a quick 'annual' budget on paper or in a spreadsheet.
The spreadsheet version starts out with my annual salary, then minus my pre-tax retirement/HSA contributions. Then I do the math to estimate taxes, including SS and FICA. With my annual post-tax approximation, I take out 'annual'/non-monthly known expenses like car/house/renters insurance, post-tax savings, etc. Here, I could also estimate house repairs, vacation budget, clothing budget, hobbies, etc, though I don't usually. Then I take what's leftover and divide by 12, and that's my monthly budget. With that, I run the number on my 'planned' expenses like rent/mortgage, groceries, utilities, phone, gas/transportation, and any entertainment/restaurant/going out money I want to budget out. This lets me know if my budget is at all reasonable. If I have a bunch leftover after my known/expected expenses, I'm good. If I'm close, or heaven forbid, negative, that's a wakeup call that somewhere up the chain, something needs to change.
I like this method because it takes a bunch of 'required' spending off the top, and divorces the number on my paycheck from the amount of money I actually have to work with every month. It's also a good reminder of how much I need to set aside to meet the various irregular/annual expenses. When I was renting, it was a good tool to keep a reign on what kind of housing budget was reasonable.
