True, I wouldn't go series on your "breakout projects." I'd go self-contained stories. Probably instead of your five part series, I'd do three different "worlds", and write one full story in each world. The fourth book would be a series of short stories in all your worlds, and the fifth book (and future books
) would be whatever your readers indicated they wanted at that point.
That way, if you get cut off, or if life happens, you're not making people angry by leaving things hanging.
Look at how angry Jordan's fans were that he had the gall to DIE before their books were done. Or how angry GRRM's fans are that he is basically going to every convention on the face of the planet .. and when he sits down to write, he's writing Wild Cards stuff instead of Song of Ice and Fire. Now , those two are famous, so anything that comes out will still get significant sales.. but if you're not famous, the last thing you need to be doing is alienating your readers.