Mine have never been done on my 2012 Tundra. The truck currently has 286,000 Km on it. There has been no noticeable power loss, difference in fuel economy or rough running at all. I’ll change them out and update this post after the replacement and post road test are done. I’m going to say the replacement interval is somewhat flexible with Iridium plugs
I just did the 60k oil change. According to the scheduled maintenance it states to change spark plugs every [EDIT] 30k for emissions warranty. I'm not worried about that.
I've yet to change the plugs on my Tundra.
I have a 100 mile roundtrip off-peak daily commute, so most of my miles are highway miles at low revs. I do haul and tow occasionally, and also put a few miles off road on the ranch, occasionally in 4WD low.
So, time to change them? If so, anyone recommend a good brand?