I hadn't checked for at least a year but had no real reason to do so as I had only had a couple of fogged negs and that had always meant I screwed up with the Graphmatic etc. For some reason I decided to run a light inside and found a bellows that resembled swiss cheese along the corners. I mean a dozen holes some as large as 1/16". Couldn't understand why I had no real problems but I guess it is because I habitually toss the dark cloth up over the bellows just to get it out of the way and that must have saved me. Sometimes you get lucky.
To repair I remembered others saying they used black tool dip and thought I would try it before spending a couple of hundred on a new bellows. I expected a sloppy looking hack job but I have to say this stuff is a miracle product for Linhof at least. Without looking VERY closely you cannot tell it has been patched. Obviously I don't know about longevity but I'll report back next year.