I got just shy of 18,000 miles out of a Praxis Works big ring (which was a 48T, I dunno if that makes any difference.) At that point, it had a handful of chipped/bent teeth, so shifting was either fine, or not fine. Probably could have extended it's life with some filing-- the teeth weren't getting that "shark-tooth" shape and it wasn't aggressively wearing out chains, but I just took it as an opportunity to replace it.
I only have about 8,500 miles on my RaceFace narrow-wide, and 3,000 on the Praxis Works compact on the other bike-- so replacement for those is quite a long way off.
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