On Fri, 22 May 2020 23:38:33 +0000, bob prohaska wrote:

Today I encountered a bicyclist whose freewheel had simply let go. It
didn't drive at all, but neither did it make any obviously awful noises.
He'd already arranged for someone to pick him up, so thre wasn't any
point in exploring further, but I was very much surprised.

My guess is the gunge in the hug had caused the pauls to stick. When I
started using grease in the works, I had to use a medium grease so the
pauls didn't stick up. Thankfully, we don't have freezing weather in
winter, so I didn't have to adopt seasonal grease changes

The freewheel on my bike is coming up on 40 years old, runs quietly and
seems to work fine....should I be worried about it? Never done anything
to it except oil it once in a blue moon.

As always, it is a YMMV, but if it ain't broke, don't fix it.
After that time, I'd just watch for it becoming loose and consider a ball
bearing replacement, and doing that will tell you why I started using
grease in the first place.