Maintenance schedule inconsistency

[Tommy Boy]

Hey guys and gals;
new to this forum but have owned a 2000 ITR since new.
I noticed in the maintenance section, here, there are a few items listed that are inconsistant with the owners manual;
Example in my owners manual which is quite different than here:
spark plug replacement at around 90k miles,
cap and rotor also at a much longer time frame than mentioned here,
and no mention whatsoever of inspecting and possibly adjusting valves at any time schedule
(so, I'm not sure if we have hydraulic lifters, which I naively assumed)

Has anybody else noted the difference from their owners manual? Anybody have an explanation as to what maintenance schedule should be adhered to.

[Dave_B]

A lot of people track their cars, and drive outside of "normal" driving. Being that it is, most replace things sooner than recomended.

I change plugs every second oil change. On the street car that is, so every 12k miles.

[Tommy Boy]

A lot of people track their cars, and drive outside of "normal" driving. Being that it is, most replace things sooner than recomended.

I change plugs every second oil change. On the street car that is, so every 12k miles.

Well yes, I can understand that.
However, as far as the valve adjustment goes, there's no mention of it anywhere in the maintenance literature you get with the car.
So, I'm wondering if this a new thing owners have realized that should be done? What would be the symptoms if the valves were out of adjustment? Also, I know it's a stupid question, but I thought they were still hydraulic lifters in our cars?