There is just so much you can get out of running your own niche websites. Apart from making some extra cash in affiliate and advertising revenue from a specialized website, you can also learn when the bigger trends in the niche coming in season again.
For my San Francisco Tips website in Dutch, I can see that the people in The Netherlands starting to think and research their summer holiday options in early January. For three years I’ve seen the same trend happening for my site with tips for San Francisco.
Here you see that traffic is increasing significant for the first two weeks after the new year has started. Amazing how consistent this is over the years.