asianthree, I don't think you meant to imply that you can pay all your expenses plus a mortgage from your rental income? Am thinking you are saying that with a little financial discipline, you plan to pay your mortgage off in 5 years and that the rental income is helping to do that.
It would certainly reduce the stress and timing of your future retirement move if you can do this. It's also nice that you pretty much know exactly (or almost) what you need when you finally make the permanent move.
The particulars in any one situation can make it worthwhile to buy several years before retiring. Just know what you're getting into.
So I guess I would say, do the math for your particular situation. It worked out for us, but there is some additional work and worry involved for most. The other downside was that when we did visit, we spent a lot of time on landscape work, touch-up painting, heavy cleaning, etc. No one takes care of your place like you would.
It would also annoy the heck out of me when tenants moved things around - mostly stuff in the cabinets (although I have to admit that once in awhile someone had a better idea
Most tenants here, however, treat your place very gently.