We've had a Demco tow bar for 10+ years.
Twice, even though it was working OK, I've sent it to Demco. I paid the freight, and they worked it over, replacing some parts, updating the configuration, etc. , and shipped it back to me in a week or two at no charge.
I appreciate the way they stand behind their product.
Also, their primary business is making agricultural equipment for farmers. That stuff gets much much harder use than any tow bar, and makes me feel confident in their ability to engineer products that can stand the test of time.
I guess I really didn't answer your question - If you don't feel like it's the same as it was when new, then have it checked out. I suspect that since you've asked the question, something in your mind is telling you that factory inspection and perhaps repair would be a good idea.