I've noticed that on my saltwater rods my grips get far more abuse.
Me too. My 12 wt Sage is missing 3 top rings and another is loose. An 8 wt Orvis Boron has 6 up top loose. As soon as I get a new 11 wt, the 12 wt will go in. Both those rods have cigar and not Wells grips, so there is less surface area for the glue joints between rings. Once they get loose, they don't last long. I don't use the boron any more, but probably should get it fixed to have for another spare. The 12 wt, I can't get repaired yet because I use it nearly every month of the year.
It's perfectly obvious that I desperately need an 11 wt., even before modern 9 and 10 wts.