Old stuff breaks, even stuff that was good when it was new. If antiques are your hobby then it can be a fun past time to restore and use old stuff, but for me a 30 year old ATV isn't going to be reliable enough. With it being your dad's ATV nostalgia certainly comes into play also.
I don't like working on things any more, I just want it to start, be able to run it hard and put it up without undue maintenance. I tend to run newer equipment for that reason. My time's too valuable to be constantly fixing things that I need to work right now.
