At what mileage should I change my 2005 Toyota 4Runner SR5 4dr V6 timing belt?

80-100k. dont go over the mileage as if it breaks, major damage will result. Roy

Good news... you have a timing chain. this is not something you need to replace. You just made yourself $1000 it would have cost to do a "timing belt" if it had one - spend it on your wife!