How frequently should it really be done?
How often did you guys do it? I
s it difficult to do?
Thanks!

i looked into this as a future project for me to be doing in a few weeks. I looked on All-Data and it seems pretty intracit, but one of my teachers told me its pretty easy. The only thing you gotta worry about is you have to shim the valves and your gonna need to have different thickness shims laying around *according to one of my teachers and all-data*. Im planning on doing this in maybe a week or 2, so when i do it, ill take pics and do a full write up on it.

It won't hurt to check, but very rarely do they wear out of adjustment.
We don't even stock shims at the dealer, it's that uncommon to replace them.

With that said, you don't need to have shims laying around. You will be wasting your $$.
What you do is measure the clearance, if it's off, measure the thickness of the installed shim, consult the chart in the BGB for the new size, and order.
When they come in, replace.