My niece is starting off budgeting! Since she doesn't have consistent hours, she's having a little difficulty with it, so she started rounding her numbers. I noticed the rounding wasn't going in the right direction! If you are averaging, rounding or estimating, overestimate your expenses and underestimate your income until you have about 3 months under your belt of monitoring your finances. Then you can adjust your budget with more realistic figures.
Hope this helps 🙂