I own a Espirit 120 purchased in 2016... the focuser grip bands did literally fall off after a couple of years. But they didn't disintegrate, the rubber just separated along one clean break. I think SW's adhesive is really poor and it can't hold the rubber rigidly to prevent breakage.
Knowing that this would be hard to replace, I used double-sided tape and very carefully wrapped the bands back on the metal knob which was first wrapped with a tape layer. This worked, and I haven't had any additional problem with the grip bands since then (probably at least two years). I'd recommend that you try to salvage the factory-supplied bands if they can be re-used.... the rubber seems to be durable if it's tightly bound to the knob.
Edited by Loren Toole, 02 August 2021 - 09:50 PM.