how often does a toyota pick up 1990 with 225,000 miles need timing chain changed?

The biggest wear item isn't the timing chain, it is the guides. The 22RE motors come with plastic timing chain guides that will wear out and eventually cause big problems. There are aftermarket companies who sell metal guides, so if you do tear it apart, replace the plastic ones. You can usually tell that the timing chain and guides are becoming a problem when you hear a metallic clanking/grinding noise with the engine running. With 220k, there's a good possibility that is occuring.

if you have a V6 VZE like i do on my 90 i would suggest every 85k to 95k because they do not have timming chain its a belt and thoose wear out pretty quickly

do you know how to check if it a chain or belt? do you know prior history of the vehicle, (owned it for long), there are gauges that can determine the wear of the timing belt, and how many miles approx. it has on it. if you hear the "clanking" sound, (stated above) then yes, probably, and that would go away as you accelerate, then it is time. things not considered if you do it, is it an internal or external water pump??? just a thought

i agree. replace the guides with metal guides. and while you have everything ripped apart, replace the front main seal and the water pump if want to (its like $30 at a general parts store). thats what i did on mine @215k

My '94 2wd pickup started making noises around 180k. Had the chain replaced and now at 255k it is still purring like a kitten. Just get it changed before damage occurs. The sound is pretty obvious.