My mom had ~140,000 miles on her Saturn Vue with the Ecotec, plugs looked just fine. I did replace them though.
Brother in law had 156,000 on his '04 F150 with the 5.4L 3v, and they were shot:
Luckily got all 8 out with no broken plugs.
Brother in law had 156,000 on his '04 F150 with the 5.4L 3v, and they were shot:

Luckily got all 8 out with no broken plugs.