Definitely keep an close eye on the wear on the pins, bushings, and sprockets. Also do a cursory check on the rollers and idlers periodically. Like anything else, maintenance is the key. It's way cheaper to replace or turn a worn part than it is to run it to failure. Undercarriages can get very expensive. If the undercarriage is currently in good shape and you're using it for just recreational, non-commercial use, you should be in good shape for a long long time. Congrats on the purchase, I would love to have one to use on my property full time. Just guessing at what you'll be using it for, I'd highly recommend finding a good used root rake that'll fit it.