I checked on the spark plugs in my 2015 Prius C by pulling #1 and #3 to see what they looked like after 168K miles. They're almost brand new. Both insulators were white but with a bit of tan color on one side. I wasn't able to check their gap because I didn't have a gauge that could measure 0.032". At this rate they may very well be lifetime spark plugs. I set a reminder to check them at 250K miles and regap them if needed but I expect them to be just as clean.
