You can build a reputation as an expert spreadsheet developer. This certainly doesn't hurt the resume. Using Excelville.com to sell spreadsheets allows you to set up a profile with your work, biography, and other info that certainly makes for good conversation material during interviews.
Protection of formulae : How often have you forgotten to protect the cell contains the formula that took you hours to test and perfect. It takes one instance of honest human error, and that formula is gone.
You may also want to track your current spending on one sheet with columns for different categories. Some individuals will list the budgeted amount in one column and then list the actual amount spent in the column next to it.
Once you design the type of budgeting spreadsheets you want to use, it will be easy to copy it for subsequent months or years. You can also use just one sheet and create tabs for each month.
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