Lots of rumours and fairy tales to be had!
Ex-dealer mechanic, so I have always done all of my own work.
Mine had been adjusted (or so I am told) at about 50,000 miles. I got it at 53,000 12/2013. Adjusted it at 71,000 myself. Six of eight exhausts were tight. All got adjusted to maximum clearance then. Intakes were all OK, so that cam stayed in.
Just did it for the second time last week. 126,700 miles. Again with the exhausts, six were tight. Several of the intakes had opened up a little, NONE had gotten tighter, and all were easily in spec.
Not what I expected...but I measured twice to be certain. Again I left the intake cam in.
Do what you want, but adjustments do become essential after a while. I would do the first at 25,000 miles, and then every 50,000. They seem to be quite stable. I do not rev the thing all that much, and yes, that is likely to matter.
datsaxman