Generally speaking, any bike in the '02-'08 years range will need a bunch of maintenance performed whether you can see stuff worn, needing replacements etc., or not. Plan on tearing the chassis apart for a thorough cleaning & inspection, repacking all bearings, replacing oil/grease seals, replacing worn brake & steering/suspension parts, readjusting cables, valves, clutch, fluids changed, etc. Some bikes might need refreshing after they are only two years old if they are abused & neglected. You can get a lot of money wrapped up in any used bike real quick.
Best advice I got is buy the year & model of bike you really want... be patient and shop for that bike in very good condition... and plan on putting a bunch more time and money into it than you estimate it might need. There are many good used Hondas out there (some are cheap) that only need about $1500 in parts/supplies and a couple hundred hours of your time... to make them like brand new again. Maintenance/repairs after all that become predictable and easy... so you can end up with a better performing and much more reliable bike than you can buy off of any showroom floor using that strategy.
Ain't nothing you can buy that is ever ready to ride. New ones are just as needy as many used ones are. Have fun shopping!