I too use an Excel spreadsheet. A few years ago I took a weekend and looked at EVERYTHING I was spending money on at the time, added it up by category and divided it by 12 (I get paid monthly). I have everything on auto pay that I can. If I overspend on restaurant food, it comes out of my grocery or entertainment category. AND!!!!! I LOVE my Sinking Funds category - it's the biggest thing that helps me with all those things that pop up over the year!