As far as cleaning brushes is concerned, it really shouldn't matter whether the brush handles are plastic or wood if you promptly wash and dry them. Any brush will lose hairs over time, so it should be expected, but I see no advantage to plastic handles, mainly because the hairs are glued in or fused with heat, and that gives out over time as well. Besides, I never liked the quality of plastic brushes. I was able to maintain a healthy supply of brushes, some over 20 years old, by making sure the brushes were set out to dry soon after cleaning, and developing good working habits with my students regarding the proper handling and use of brushes. I would order only about a dozen replacement brushes per year for lost or broken brushes, just to maintain the supply. The essential thing is to be able to have a large supply of brushes for a variety of uses, but when you have limited budgets, you should kind of set your goals for building an inventory
over several years, then maintain your suplies as best you can. This really applies to all non-disposable equipment in the art room.