You do not need to change…
You do not need to change the plugs at that mileage. Honestly you can get double that mileage unless you develop a miss fire. My 2004 were changed at 220,000 and my 2012 highlander has 170,000 on the original pquickly. Am guessing you have the 6 cyl. engine. The front 3 plugs are easy to get to. The rear left plug and rear right are a bit of work but can be changed out with a little finesse. It's the rear middle plug where you have to remove the air intake etc. To change it out. I would find a good local mechanic when you need to have the work done. Don't let the dealership pressure you into changing these too quickly.