I started out just for fun. Some time later, I started monetizing everything, cause even 15€/month would be better than nothing, right?
Eventually, I liked my own videos so much (Yes, I re-watch my own videos. Is that e-peen masturbation? e-masturbation?), I got a bit miffed that more people werent watching my hard effort. So I set about on getting more views and more subs.
I noticed there were no reviews of the new CB500s from honda, so I went and did a testdrive and review of it. And not only I found out that I loved doing that, that enjoyment showed in the video, and it became an instant hit, cause a) there were no other reviews (only a 3 min "review" by MCN),and b) the fact that I was enjoying myself immensly filtered through.
So I kep doing them. Some went crazy popular (cbr500r, mt-09), other not so much, but the original objective was accomplished: more subs, more views.
As a bonus, I also got:
-A new video type I really like to do
-Quite a nice sum from the monetization, amounting to something like 10% of my income (keep in mind, if you made what I make here, it would problably not even cover your rent/utilities bills.... min wage here is 475€, average is around 800...).
So... just do what you like to do, it'll show. Keep an open mind for something that might "fill a niche", and when I doubt, try it out! You might like it (like I found I also like the end result of music videos. Not the editing, but I love the end result).