[xeaxkvsk] Amortized spending app

The program tracks your spending and produces reports on daily, weekly, etc. spending.

For purchases which you use for an extended period of time, provide an interface to specify the time interval, and it computes amortized spending per day for you.  (Use the interest rate on a savings account.) All this already exists. We just need a nice way of collecting all the data.

This attempts to partially solve retrospectively whether you should buy.  While you cannot easily assess absolute utility, you can compare whether some purchases are worth it relative to other purchases.