...is it harmful to the piano? Rather than the twice a year recommendation, I want to have my piano tuned every month. Is there a harmful consequence like loosening of tuning pins, etc?

If your technician doesn't work the pins too much, it should be fine to tune every month. After all, many concert instruments are tuned and checked every day and are just fine. It all depends on the skill of your technician.

This subject is mentioned in one of the tuning home study courses. Apparently there is a piano at the Emil Fries School of Piano Technology that is practiced on by tuning students day after day, year after year with no pin block problems at all. I imagine that new tuning students are moving those pins around a great deal. In some restaurants there are pianos tuned every week with no problems with the pins and block.

The only problem that you might encounter is that there will be little or no tuning for your technician to do on some visits. He/she may just have to wave their tuning hammer over the piano and collect a check for ten minutes of work.

The biggest problem most new tuners have is moving the tuning pin to much one way or the other. - back and forth, back and forth missing the mark every time. This makes for an unstable tuning.

Welcome!

Thanks for the tip, Jerry!

Thanks, Byron! That's quite reassuring!