I had a Blue Ox Alladin (aluminum) towbar that I bought new in 2004 and used until I replaced it this year. Had it inspected periodically at FMCA rallies, refurbished by Blue Ox (new steel extension tubes, triple lug brackets, etc.) in 2017 and I cleaned and lubed it after every season. That's probably longer than most would keep theirs, but more importantly than how I serviced it, I knew how I used it. No "slam" extensions when leaving for a day's drive, no forceable lock releases on the extension tubes at the end of the day, covered or indoors when not in use. The more abusive the utilization, the shorter the safe usable lifetime. Take good care of it, and get it professionally inspected periodically. It's a prime safety piece of equipment.
Mike and Cindy
2016 Tiffin Allegro Open Road 34PA
2018 Chevy Malibu