How long should the bed PEI sheet last?

Is there a ballpark number of prints that the PEI sheet should last? I’m having trouble it developing bubbles raising off the glass. I’m going onto my third one in ~18 months, printing about 10 items a month.

I mostly print parts that take up a significant portion of the XY build area, out of some of the finicky plastics like ABS and Nylon. I’ve recently had my Nylon parts look like they’re ripping the PEI off when they shrink. I read through and realized that I shouldn’t be letting the bed cool all the way then re-heating to remove, but some of the bubbles developed mid print.

So yeah, is this about what’s expected for the PEI sheets? Alternatively, is there a print bed type that I can print nylon directly on? I’m OK with using glue since my prints are usually 5-12 hours anyway. Its just that replacing the PEI sheet is a pain in the butt, and since nylon doesn’t stick to it anyway, seems wasteful.

PEI sheets are basically a consumable item like the tires on your car.

The PEI sheet is more or less where the rubber meets the road in this application.

Plastics like ABS and Nylon are the roughest on PEI from my experience. They stick really well and can end up taking the PEI sheet up with them when they warp or when you remove the print from the surface.

Nylon sticks really well to glass and that’s one of the applications for the Modular bed system. It’s got a glass side and a PEI side that you can flip over when using different plastics.

When printing with Nylon on glass or on PEI a small layer of glue-stick will help with removal as it adds a barrier between your part and the bed.

Careful removal of parts and removing them at their recommended removal temperature can help to extend the life of your PEI sheet. As well as not printing on the same spots every time.

I use pei on my Taz but use gluesticks on it and have seen no reason to replace it. Yes, I could just do without, but it’s there and I just don’t feel like removing it. If you use gluesticks there is little if any damage done to the pei in my experience.