Looking at building up a dedicated AL crit bike. I'll be going the ebay/craigslist route and hopefully getting a group and frameset separately.

Since I'm trying to keep costs as low as possible, most of the frames I'm looking at are used. Is there a good rule of thumb for age/mileage of an AL frame? For example, there's currently a Team Soloist I'm interested in with stated mileage of 'under 2500'. This seems reasonably low, but there are other frames out there with considerably more.

Just wondering where my cutoff should be. How long does a typical AL frame last? 10000 miles? 20,000?