You can make utilities for yourself where you can put all your calculations and worksheets. This will reduce repetitive work to a great extent and help you save time for some other productive and constructive work. Apart from them, there are a countless number of other ways to use spreadsheet such as planning your tax, investment, cash flows, managing phone numbers and contact details and the like.
Rent or mortgage, homeowners insurance or renters insurance, all utility bills, auto loan or auto insurance payments, gas for your vehicle, food for home, and so forth. Once again, these are items that you cannot live without.