We've been here a week. We've been wearing masks always indoors (except when eating), on transportation, and in crowds outdoors, like in ride queues.
There are some other people doing it, but it's not exactly what I'd call a trend or even a common occurrence. Nevertheless, you should do what you feel comfortable doing.
I wear masks indoors in public places at home, so I was hardly going to change for WDW.
One thing I noticed today at MK: a lot of CMs were wearing masks.
ETA: Bring a lot of hand sanitizer with you. There are very very few hand sanitizer stations anywhere in the parks now, I'm sorry to say. The only ones I've noticed are at the TSMM exit (and it was empty yesterday afternoon) and inside, near the entrance to Mama Melrose's. Other than that--nada. I was very disappointed.