How long until prop O/H

Although 900 hours is less than the time in service for most of their
models, ten years is well in excess of the recommended time for most, which
seems to be either five years or six years depending on various factors (at
least for a hub inspection, and probably for the blades, too).

I've heard the same thing - if your blades are OK, you may still want
to have the hub re-sealed after more than ten years, that will prevent
corrosion, etc. Its not terribly expensive to do that vs. full blown
overhaul ($1000) and it takes care of the moving parts.

If you do overhaul, shop carefuly, the Aviation Consumer had an
article on this while back. Some shops are quite enthusiastic about
rejecting perfectly good blades, apparently.