[jlees]

The issue is that of avoidance. If I have to tell an app I've been bad, I'm more likely to avoid telling it at all. (Like not getting on the scale when one knows the weight won't be good news.)

Sure, highly motivated users will track everything, but it doesn't take much to leave the highly motivated state. There's also the angle that knowing you have to report in with bad news might stop you doing the bad thing in the first place, but when the penalty for not reporting in is nil, it loses some of its power. Perhaps approaches that use human accountability or other reward systems (eg. GymPact) could help here.

[DLarsen]

Good point. This is absolutely essential.

In some circles I've described it as "a money tracking tool built for couples" and that's true. This all emerged from a chart my wife and I had been using on our fridge. We wanted to address the decision making progress as a couple and not beat ourselves up over specific failures (impulsive spending, false bargains, etc), but try to improve our process for budgeting and spending money.