I seriously regret not joining these points programs. i wasn't a regular traveler by air but over the past 20 years I have done a lot of it. I would have almost certainly, even by accident, have accumulated some free upgrades over time.

I was frustrated out of participating because before leaving the USA I was part of points programs. I save them for ages. Then when it came time for me to actually use some of them i was informed they had expired because it was a sort of "use it or lose it" policy at the time. That sucks and I just never looked back.