Then, when you've read Ron's stuff and AOPA's info', it probably goes without saying that finding someone who's owned the make/model and picking his or her brain is invaluable. Or more than one someone. Add their info' to the mix. Also, and I have a buddy who is an A & P, so it is easy for me, but talking to a mechanic who's worked on the make/model can really be instructive. There can be issues with any plane, but these procedures will take you a long way toward minimizing nightmares.
I realize you asked for per-hr. costs, but these things all have to be considered and budgeted for. I have known a number of owners who found themselves in a state of shock when faced with costs that experienced owners are accustomed to or have grown to expect. [I consider my Baron to be in good shape, if aged. Last week, in two hours of casual, local flying, both the turn coordinator and then later the DG went out, unrelated issues.]
Another thing: I've owned several small planes, and on the first one, the broker I was using handed me a worksheet of expected hourly costs for the plane I wanted, which was a Cessna 172. He had a lot of info' on there, and after I'd owned the thing for a year, his numbers were so far off it was laughable. He didn't lie to me or anything, it was just that no one can tell you how much you'll spend on tires, lights, oil lines, baffles, any sort of thing. I had a partner in that plane, and we would often laugh loud and hard at the estimated costs the broker told us about at the beginning.
