From my DP101 instructor, circa 1978: “If you have to do it more than once, write a program.”
Been living that one ever since. :)
Back in the 1970s, I was doing taxes for my family and relatives. I wrote my own tax program for my Apple II in 1978, and continually modified it as needed. Should have marketed it, but missed the boat on that. I later bought a program, I think it was called Accu-Tax which pretty much did what my program did and stopped updating my program. Back then the Feds allowed lots of deductions that complicated programming; now taxes are simple enough to do manually.
As for spreadsheets, I pretty much used all of them including VisiCalc, and preferred products that worked on my CP/M processor on my Apple-II.