I have a 610 Touring bike and from what I'm told, the parts are quite good and would cost a few hundred to upgrade. If I spend that much, I would probably just buy a brand new bike.
Alternatively, I could spend $200 for a complete overhaul (complete disassembly, tune-up, replace cables, clean all bearings, adjust anything else but no major part changes).
Would this be worth it to keep the bike for awhile longer or just save a bit more and buy a brand new one? I'm told the Miyata could last me for ten more years easily, but some newer frames might not (sorry for such broad statements, as I'm not a bike expert).
I use my bike as a commuter, at most 2 seasons out of the year.