If you are a professional who is installing insulation all the time? You absolutely need that mask.

If you’re a flipper who buys a new house every year or two and usually replaces the insulation? You should wear a mask.

A homeowner who installs it once, maybe twice in their lifetime? Eh. A lot of PPE mandates are about doing it often and professionally where you can get a lot of exposure. Or if you already are at risk. If you have respiratory issues then if course you should wear a mask. If you have healthy lungs and plan to do this task just once in your lifetime, just having decent ventilation and not shoving your face in it is fine.

I’d wear gloves, but more because the rafters probably have splinters and rusted old nails or staples or whatever. The skin irritation from fiberglass lasts like a day or two and doesn’t have any long-term impacts, but I also find gloves aren’t as inconvenient as masks.

Eye protection is a must. I don’t mess with that.

Or you can just pay the extra money for Rock Wool and get all the other benefits that come with that too.