Sometimes a "tune up" involves replacing parts, especially shift cables and housings. Other times it involves much more involved work. I put the word "tune up" in quotes like that because many people pull their old bike out of the garage where it has been sitting for a year+ and when it doesn't work, they think it just needs a quick "tune up". In reality, it has siezed cables and perhaps a broken part that isn't really made anymore.

I worked for years as a mechanic in a shop in a major tourist area that had a focus on cycling. People from nearby cities would pull their bikes out once a year, pack them up and get to town and realize the bike doesn't work. Then they'd run over and ask our already slammed team to do a quick tune up. Then they would grouse when told they need all new cables and housings due to rust, that their old thumb shifter needs rebuilding or replacing, and the cost was going to exceed $100.

We had boxes upon boxes of old parts lying around to be used for rebuilds / cheap band aid work to get someone through the weekend, etc.

Do these quickie craigslist guys have these abilities?