Manners: huffing/coughing and apartment living, hotel stays
if you're that concerned with people hearing it and you live above the bottom floor, try putting your vest on a table instead of on the floor, that'll create a buffer area that will minimize how many sound waves make it though the floor to the apartment below you, as far as people hearing you in rooms next to you i wouldn't worry about it, it doesn't make that much noise and as long as you don't have your vest or nebulizer right next to your wall they probably can't hear it