My basis for saying that was the observation of the HG condition at ~187k. It hadn't started leaking but it wouldn't have been long before it did. So I'm just suggesting that on the first generation of Toyota iron blocks and alloy heads (22R, 1FZ, 3VZ, etc) they hadn't completely figured out the dynamics. The 3VZ (3.0L) head gasket issues were probably exacerbated due to #5 being a hot spot and it was mostly solved by dialing in the composition of the MLS gaskets to the point that the 5VZ (3.4L), the short block of which was very similar to the 3VZ, didn't have the same extent of problems. Also, not all 3.0L engines went bad and some do now have 300K on the factory HG. The 5VZ and 1GR (4.0L) still had lingering HG issues but it's down to rare. I'm not saying that doing a preventative HG and timing on a 22R-E is absolutely critical. Just that it's not a terribly difficult job for the peace of mind. The only hard part is to do it right requires dropping the oil pan, which is a PITA with IFS if you have it still, and getting it to seal back up is a little bit of concern. On a V6 or V8 I would weigh the risk/benefit of such an aggressive HG approach differently, so I'm thinking specifically 22R. I'm also a zealot about using Toyota Red (silicate-free) coolant, which should have been beneficial to HG life but there was clear evidence that the HG was pretty far along in failing between #3 and #4. I suppose it would be better to say to at least inspect well down in the timing cover when you do your periodic valve lash adjustments and to do leak-down compression tests at the same time.