These are what I removed out of my prius when I swapped out the plugs. Assuming they are original and since there is no service history by toyota having changed them, I will say these have 160k* miles on them as that was around the mileage when I took them out. They are said to last 100k.
Maintenance schedule says 120k miles (or 12 years). Too, the recommended replacement Denso plug is now slightly hotter: in the part number the 20 became 16.
I was able to get 192K out of my first set of plugs on my 2010 before I started getting a misfire under load. I purchased a new set of the Denso plugs from Ebay or Amazon. (Its been long enough that I forget which) They came in boxes that looked authentic and the plugs looked authentic to my eyes anyway. The second set lasted only 70K miles before I started getting a misfire again under load. When I pulled them out the center electrode was almost gone. I believe they were not authentic Denso plugs. Your plugs look like they have been around the block a few times but not bad for 160K miles.
I always replace the plugs after buying a car but yea they dont look bad and I will keep them as back up.
In USA it is 120k miles schedule, in Europe 60k miles since European not get used to long reliability of Toyota cars. European cars broke down much easier. After checking mine at 60k miles, I put them back and check it again at 100k miles, it is still really good.
