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.
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.
You could make money doing something you love (or like [or maybe not so much but just really good at]). It's great to see a spreadsheet come together, and usually a lot better than what you originally envisioned. Especially when the dang thing works.
Spreadsheet templates are used for many reasons and each template vary according to the purpose it is used for. Spreadsheets are designed with different calculations depending on various needs.