Create a Check Register Reflection

It's helpful to keep track of your balance on a spreadsheet because it does most of the calculations for you. You are more likely to make a mistake and throw off your balance more than a computer.
I can't think of a very bad disadvantage other than other may be able to see the file on a computer. But its smart to keep track of your balance just in case you ever suspect that you are missing any money. You can always go back and check each entry.