A typical person will do 2 or 3 transactions in a normal day - that's about a minute of work inputting them in to Excel or Wally or something. And yet they don't. I don't think knowledge or forecasting is enough of an incentive for people to want to record what they spend. That is the problem that needs solving. At least, I think that's the problem. It could be the case that failing to control what you spend just isn't enough of a pain point for people to need a solution. It might be worthwhile testing that before writing any code.