Are Dust Covers a MUST

Platter covers are more of a 'must' IMO to keep it clean and prevent dirt transfer to LP's. I've been using a platter sized cartridge alignment protractor that came with an old test LP record and recently replaced it with a poly platter dust cover from www.sleevecityusa.com

Get a decent room air purifier. Hel-looo! I'm using one that's like those the US Navy uses on submarines, so they say.

A dust cover when not playing music is a must.

No dust cover during playback.

A dust cover during play, is an acoustic feedback pickup, from the sound coming off the speakers.
 

  Always removed the cover from the LP-12 when listening.  Never tried it with it on.
  Bought a new ’table that didn’t come with a cover.  Ordered one from J Display case.  Much cheaper than Gingko.  Need one to keep the dust off.  Thought about just a cloth, or silk cover, but that look I care not for.

I have a turntable with a dustcover. If you saw the dust that accumulates on my dustcover, you wouldn't be asking whether they're necessary, but where to buy one.

I guess you could cut a rectangle of shower curtain and drape it on the record player when you're not using it.