>My question to all is do you treat only if you spot an infestation or every spring and fall.
If you wait to "spot" (as in see Varroa on bees) your bees will probably be dead before you realize they are infested. You should monitor the Varroa. That means ucapping drone brood, sugar rolls, or sticky boards.
>Here in Utah apistan is virtually useless.
Here too.
There are lots of alternatives. Oxalic acid vapor, FGMO fog, Sucrocide, small cell etc.
Read up on here and you can learn much about them.