If you just take pictures when the opportunity presents itself, you're probably not taking as many pictures as you should. Develop some projects that you're constantly working on.
The benefits are:
It keeps you involved with a subject you enjoy, so that the photography is enjoyable on multiple levels. It also means you learn more. I've recently started working on leaf closeups so that I learn more about trees. And I've always enjoyed photographing leaves. Which is nice.
Projects give you something to work on, even if you're uninspired. Or to make sure you stay photographically busy. For example, whenever I go on a trip, I know that I'll be able to work on several projects, even if I can't find anything else to photograph (eg. One Shot of Everyone, Pictures from the Largest Cities in the US, and Unitarian/Universalist churches, to name a few).
If you've got the collecting bug, photographing things is almost as good as owning them. And more practical that starting a train museum.
By having projects, you are taking more pictures, because you have something to take pictures of. And you get better by taking more pictures.
And someday, I know I'll be famous for my eat sign collection.