I’ll start. In my FOWLR tanks, I don’t t check PH. (I doubt my fish know or care. Lol.) In my little 20-gallon softies tank, I don’t check it either— and do nothing to track or prevent PH swings. That being said, it’s a “nice” tank, but nothing “glorious” or sophisticated. Other more advanced aquarists with more traditional reef tanks can pick it up from here...
I don't chase pH but I do have a probe to keep an eye on it. I would say you don't have to test it often but I would check once in awhile to make sure it's atleast in a normal range if keeping coral. I would say it's more important with sps, and not that important in fowlr
Just to be clear, pH is known to have substantial effects on hard coral growth, and higher pH typically leads to faster growth. I am not in agreement with folks who blindly claim it doesn't matter.
My point was that slow growth is not a problem in a reef tank, not that pH doesn't have important effects. I am bothered by the trendy mantra to ignore pH. It is just not the main priority of a new tank.