RE: How Long Do Servos Last?
Those are old Hitec servos I believe? 80's "vintage" IIRC...and they wern't exactly the greatest, if ya know what I mean...
Hitec makes some really good equipment NOW, but some of that older stuff..?
Modern servos are SO MUCH better...
I would replace them...for the sake of the airplane, and for safety...(not necessarily in that order )