Checking out a used full sus bike- what to look for?
 

TLDR: new to MTB, see a nice used FS bike for cheap, looking for advice.

I've done a fair bit of road biking (not very fast, but some centuries and real climbs) and running (2 marathons etc). Due to some joint issues I won't be back to trail running for a while, and since I'd miss the trails, I was thinking about trying MTB. Was looking at used bikes in my town, thinking I'd grab a cheap hardtail, but wasn't seeing anything I felt OK about for less than $350. Then I saw a Cannondale RZ 120 in my size for $440 OBO. From the fork and shifters in his pictures it looks most likely to be the 2013 1 model, which was $2200 new; here's a page with specs. The ad says he's replaced the brakes with Shimanos and replaced the tires recently. I arranged to go check it out this weekend.

I'm not inclined towards speeding downhill or taking big jumps, this won't be an overriding hobby, and I've heard cheap FS bikes are a trap, so I wasn't planning to spend enough to get a decent FS bike. But this seems tempting. What do you think of the deal, what kinds of possible issues with the used bike should I watch out for, and should I just pass and wait for a nice deal on a starter hardtail?

For a used FS bike check the: fork and shock, specifically the seals. Rarely do folks do maintenance on them. Also check the suspension pivots - if bushings, may need replacement for a bike of that age. If bearings, maybe new or clean and oil. It's a toss up based on previous use.

Bring a chain checker tool with you if you intend to buy it, check the chain stretch and then the chainrings and cogset. If they're worn down you can negotiate for a lower price to offset the price of the replacements

Everything seemed to be in good shape, even the chain. And he dropped his price to $400 and threw in the shock pump and a spare tube. Seemed like a rare deal. So I went for it, and we'll see how much mountain biking I get up to. Thanks so much for your basic advice!