You'll get responses across the spectrum on this question, I'm certain. Here is my .02.
I used to grind the peg feels constantly. More so when loaded, as a function of over taxed suspension. Solo out of poor form. I attended some training and learned new riding techniques, re-worked the suspension to be on par with what I was asking the bike to do, and no more grinding. Occasionally I'll get a peg feeler down, but usually when I've misjudged a corner in some way and attacked it with poor form.
If you pushing to the point of grinding parts, you are to the point of advancing your riding technique through training. This is more than reading a book. Participate as a student in a rider course where you've got direct observation and critiquing from established professionals. Check that box, then consider upgrading the suspension in order to get the bike to a point where it can better respond to what you're asking of it.
Everyone will have an opinion. For me, as the bike sits now, I can make time up or down a twisty road smoothly and efficiently with out grinding parts