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.
If you are experienced with spreadsheets you can also add extra features such as the ability to create graphs from the data you entered. Graphs make it easy to get a quick view of your current financial situation. The graphs will allow you to easily spot trends and areas that are in need of attention in order to keep you on budget.