Rocker arm inconsistent oil flow

[Hammerhead]

I don't go 6 months without opening the rocker cover to inspect the top end, but I'm an OCD anal weirdo...
I check the clearances of the closed valves when I have it open. I use a 0.013 & 0.026 to check them. if I find more than 2 or 3 that I can't get the feelers in, I do it. I don't bar the motor, I just check the closed valves. That doesn't mean there is 0.002" of wear, the oil residue does take up some of the clearance. Because I run above average torque loads, I set at 0.015 & 0.028 to allow for extended thermal expansion durations...and I'm thinking of increasing that by another thou, but once again I'm a weirdo.
If you do your own, annually should be sufficient. Personally I think any individual truck owner should at the very least do annual overhead inspections, it is your livelihood after all.
If you don't do your own, time to learn how. This procedure is one every truck owner should know how to do, it, along with the inspection you make while performing it is the best mechanical indicator of engine condition.