I re-taught myself basic algebra and trig over the last few months. It was doable because I'm not employed and I did have a deadline for myself which was that I wanted to be done before
going back to school in January.
The most important thing is to have some structure which to me means you have one *primary* book that you're studying from, or some kind of structured material. More flexible than X hours per day is something like X material covered per week.
My pacing was something like 2 to 3 chapters a week. The book I was using had tons of problems so just the homework alone took a good 8 hours in each chapter. I used my main books primarily and then used other resources such as those available at khanacademy.org and whatever else I could find as supplements.
You have to be flexible enough in your structure that you can spend more time on things that are difficult and less time on things that are easy, but not so flexible that you never achieve your goal. The problems you've outlined are simply problems inherent in self-study and you have to balance them.
Thing is, we're inevitably our own worst teachers no matter what we do. If you really want to learn something well, taking a class is the way to go. I did self study mostly as a review, and I sometimes do it for things that I'm really super interested in or motivated by. But I have a lot of unfinished self-study project lying around, like my attempt to read the complete works of Shakespeare, Kant's Critique of Pure Reason, and a host of other unrealistic goals. Of course my attempt to self-learn physics has been going on for over a decade now which is why I'm
going back to school for math.
-DaveKA
