This is a really good practice. Aside from the obvious that dust in general isn't good to breath, many of the exotics (and some domestics like walnut) can really be a health problem from as little as "sensitivities" all the way to full blown "I think I'm going to die!" situations. The sensitivities can grow over time, too. I had a locksmith at the house a number of years ago who used to be a carver. He suddenly got sensitive to walnut and as time passe, any wood dust started to affect him adversely. He had to give up the carving and while working his job as a locksmith had to wear PPE including gloves when even chopping out mortises with a chisel. Personally, I can't handle (literally) bubinga. It makes me break out.In the meantime I am trying to develop a habit to wear a mask when I work, especially with exotic woods.