If you buy something because it's undervalued, then you have to think about selling it when it approaches your calculation of its intrinsic value. That's hard. But if you buy a few great companies, then you can sit on your ass. That's a good thing.
Investing is where you find a few great companies and then sit on your ass.
If it is wisdom you're after, you're going to spend a lot of time on your ass reading.