I recently did a plug change at 11k miles ago.
The time sert been in the head for seven years and 97600 miles with no issues to the time sert to the spark plug fitting. I say that because there is an issue with the time sert to head fitting very tight. Timesert itself is not loose. The plug looks to be burning great. Color is like the rest of the 5 spark plugs with virtually no compression loss via compression gauge.

Only issue is I have been getting oily residue on the threads, so it could be a ring or valve guide issue in that cylinder. Engine is going on 322000 miles.

I already checked the spark plug tub seal is sealing up good on that cylinder. Could be I fouled up on the oversize reaming in preparation for the timesert.