YES! Always use Never-Seez 0n spark plug threads!
Steel screws threaded into aluminum need Never-Seez.

A mechanic who says otherwise should be avoided.

I had that problem when I first got my 850, the plugs did not want to
come out. After struggling to remove, the threads were galled and I needed to run a tap to clean the threads. A thin coating is all you need and the problem
won't reoccur. I needed to do the same with the head cover to access the plugs.
More steel screws, binding up in the aluminum head...Never Seez to the rescue.
Also use on O2 sensors, taking care to keep the grease off the sensor element.

Bill