Toyota is the Japanese word meaning "very hard to kill."
If you have the V8 you should preemptively "fix" the secondary air injection pump. See this thread:
http://www.toyota-4runner.org/4th-gen-t4rs/174030-secondary-air-injection-pump-failure-v8s-important.html
It's a rare case of "if it's not broke, fix it ASAP."
Other than that, Toyota's are really finicky about using OEM replacement parts even on seemingly plug and play items like spark plugs and O2 sensors. Non-OEM won't kill it but it will run like crap. Buy once, cry once. Don't cheap out on replacement parts.
Also, after 100K miles check all of your "lifetime" fluids (Trans, diff, T-case). They are worthy of examination if not replacement.