Here's a case where they really don't make them like they used to.
When I was young we had an antenna rotator that cost about $100 - the equivalent of about $650 today. I don't know if that rotator's still on the roof, but if it is there's a very good chance it could be working just as well after 40 years. Folks, today's rotators are also priced at about $100 but remember the cost of a car has gone from about $4,000 to $30,000 in that time. Can you really expect a $100 rotator to be a lifelong investment?
Personally I think that if anything under $500 lasts you five years, you win. And you should probably expect a rotator to last that long, except in cases of extreme weather or really heavy antennas. Sometimes they don't, and honestly that's just bad luck. We live in a much more disposable society today than we did in 1970 and it's hard to interest the public in something that will last 50 years when the average piece of consumer electronics hits the recycle pile after about 36 months.
Believe me folks, I've looked, I've analyzed, I'd love to be able to offer you a $1,000 rotator with a 20-year guarantee. They don't exist, because no company wants to make them. That's not the economy we live in.