If you know the yearly, then that is the allotted amount in the company budget for you. So, in the big picture, you are being paid yearly. Especially if you are salary or contract. I have switched to making a yearly budget with monthly categories, and the yearly costs are much easier to factor into. My budget became more simplified and less stressful. Also, another benefit is that I save for an average cost that is usually higher than most months, and the high cost months are less troublesome to plan for.

I try to calculate net income: deductions and taxes removed from gross income. Overall, I feel better as I can plan ahead of time and don't need to do it every month. Still need to keep an eye on following the plan and for anything that changes it. I don't just plan it either, I execute it.