Most people are going to be running a different suppressor/rifle/ammo combo which can result in different experiences.
I run a few short barrel AR15 uppers, and I first started off wiping down the outside of the bolt carrier group, the upper receiver, and the receiver extension between 200-360 rounds. Things get grittier as more rounds get fired. I have gone longer intervals without cleaning, and adding lubrication keeps thing running, but things become nasty, and I hate the smell.
I have had only one strange issue manifest in my suppressed Colt 11.5” upper. I replaced the original bolt with an LMT enhanced bolt. Although I wiped down the outside of the bolt carrier group, upper receiver, and extension, I hadn’t inspected the extractor. After approximately 700 suppressed rounds I experienced a bizarre failure to extract where the extractor “dog-eared” the rim of a 223-case leaving the empty case stuck in the chamber. Cycling the bolt would not extract the case. I had to borrow a cleaning rod, and the round popped out without any effort.
I found that the extractor of the LMT enhanced bolt was filled with carbon, and gunk. More carbon than ordinary mil spec bolts with similar suppressed, and unsuppressed round count.
So yeah, clean when you can, and keep an eye on potential failure points!