I go through phases. From 88 to 95 all new. From 95 to 99 used. From 99 to 2002 new. From 2003 to now used. The new phases align with when I had money mostly. Roadie bikes have all been used however. Someday I will have a new roadie.
I go through stages, usually my budget or current financial status.
on my Current bike, I bought the whole thing off Ebay in spring 04,
(my Karate Monkey) but since I have built brand new wheels(surly hubs to Bontrager Disc rims) New Handle Bars (Jones H-Bar)new stem(Ringle on clearance for $7 at jensen) New Stainless front sprocket(Surly) and a new Saddle(Fizik Nisene Cow).
and of course new tubes, tires, grips, chains......
Right now I am looking for a cheap but decent roadbike or road project, and then in the spring looking for a geared 29er for racing..... Might have to go new not much used availibility.....
well i learned my lesson when buying used, i bought my first dually used good price really well specced for the time,
First ride on it the the headtube fell off, a fatigue failure that just happened.
There was no sign of damage when i checked the bike out. From then onwards, ive bought new bike components. I would consider some second hand stuff but anything major like forks, frame, cranks, rims ill buy new. Id rather wait a bit longer or get something lower spec then fork out a similar amount of money on a top of the line component for it to then fail on me leaving me with a paper weight since i cant get warrenty (unfortunately this is the case in australia)