I find that the longer I run the site, the more resistant I become to the idea of ever giving it up, even if I need to take the occasional break. It is pleasant to work on something that people draw benefit from. It is especially pleasant to work on something lasting. And I enjoy the looking-glass aspect of our industry, where running a mildly profitable small business makes me a crazy maverick not afraid to break all the rules.
Pinboard is the outlier, it bucks the trend, or maybe its the trend setter. I know I've been a very happy customer for over four years.
We can learn a lot from Maciej Cegłowski.