If the description doesn't read like the owner knows anything about the bike, like not knowing the size, or if the description is something like "Litespeed titanium bike. Large" and nothing about the age or the components, avoid. If you spent the money to buy a Litespeed(for example) you'd know more about it than nothing.
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"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles