My plugs were changed a few weeks ago. I asked my tech how they looked and he brought me a plug to inspect. I swear to god other than a slight discoloration on the ceramic part under the electrode, it looked new! He asked me if I wanted the entire set to take with me. I declined as I know him for many years. He told me that the original plugs will not show any wear when replacing because of the Indium electrode.. My car had 127,000 miles at the time.
PS....As an aside, when he was working on the passenger bank, he noticed some oil in one of the spark plug valleys. Although I had the Valve Cover gaskets and spark plug seals and grommets changed a year or so ago (by another indy shop), I had him replace everything on that side again. I was proactive and had all the OEM parts ready in case this happened. All is well again.

 

Well, I did the same thing tonight. Replaced my plugs and car was not running right. It threw a code which led me to #8 coil where I found I had a wire pulled out. It took a while to find this post but since I just went through something similar with my son's GS300 I had a feeling I was going to have to cut and soldier a clip on. I was going to buy the clips you had listed but decided to spend the extra $5 for these in order to get them tomorrow and hopefully get it fixed this weekend. Thanks for all the confirmation of what I need to do.