I use the tanks until I start to have issues. I always keep a spare for when a tank starts to go just in case. Normally the cloudy old tanks are used for small prints and large prints are done on a newer tank.
Once I start to have issues I replace the tank right away so that I don’t forget to move away from the bad spots.
I can’t wait for the new long life tanks to start shipping.
I pulled the old layer off and cleaned. Leveled a table for the trays and poured in the correct weight of silicone. 12 hours or so to cure and I was done.
A quick PDMS search on here can find the links. I think there are threads for the Form 2 also.