How often should this be done?

A new set was put on about 9 years (~100K) ago so I'm wondering if it might be something I should consider.

 

plug wires are cheap enough, and they are so easy to swap that you should just do it. even if your rig runs fine with 100K on the wires

 

Yeah, I'd say you are due for a new set of wires. Be sure to get OEM wires. That cheap aftermarket crap has no place on your rig.

 

i ran autolite wires once on my '79, never noticed any differences. then again, they probably wouldn't have lasted 10 years, but i think plug wires are a wear item that should get replaced a lot more than that

i call it the "OEM placebo effect"

 

yeah, i'd say you're definitely due. and i second chickenlover's recommendation of the OEMs.

i have some NGK (blue) wires i got through sparkplugs.com (i think) for like $35/set, but although they are supposed to be (as good as) OEM i suspect they aren't as good as the ones you'll get thru toyota; my idle can fluctuate and sometimes at startup it hesitates a bit.

 

i change mine about every 10k miles also you can get denso plugs wires for 43 bucks at www.sparkplugs.com