Speakerphone "breaking up"

Occasionally people I'm talking to have been saying my phone is "breaking up" or is "choppy".

This is only while using the speakerphone. BTW, my M-Droid is completely stock. It is never powered completely down.

Turning "off", then back "on" the speakerphone seems to fix the problem during the current call.

I did a search on this forum and found a couple of posts that were relevant, most were not.

One said a possible solution might be to turn the phone completely off every three days.

I'm curious . . . what could there possibly be going on with the phone that turning it completely off every three days would solve?

Thanks in advance,

DON