The idea behind One Thing Today (or the Touch version, above) is great: focus on completing one task every day. You get that done, you feel successful.
I’ve operated this way for years. “Tonight I’ll do the dishes, and tomorrow is my writing night, and Thursday I’ve got laundry to do.” As long as I do something productive each night, I don’t feel like a loser.
So Line Thirteen does an app for the Mac and an iOS app that puts all that in software form, where each day has some task and only one task. And as much as the app seems worth it for $9 (Mac) or $0.99 (iOS), it seems like you could set up a free version with iCal or a text file. Here’s an iCal version:
If this is the way you think, there’s no reason you can’t make your own system. The benefit of One Thing Today is automatic scheduling and maybe a nicer interface – and I do think it’s neat that someone thinks the way I do and went ahead and made an app.
However, if I can do it myself with the tools at hand – especially sync-ability with NV and SimpleNote – why not give it a try?