I'm always impressed when I see people who have spent such a large amount of time on a single project. Me personally, I keep flitting from project to project, creating a prototype, or a proof-of-concept before I get interested in something else and pursue that. I think a lot of people fall into these categories, breadth first vs. depth first. It's probably best to seek a balance between the two, as then you will still devote enough time to polish the outcome, while still having the time to explore many completely different projects.