From the time we’re children holding our first paint brush, we ALL do this. We’re shown how to do this. It is the start of a dirty terrible horrible habit.
You’ve been painting with a brush, now it’s covered in paint, and you put it in the sink to “soak” off the paint. Much like the dirty dishes you’ve had sitting in nasty water for the past 2 days, your brushes rarely need to soak. They can be cleaned JUST FINE without soaking, AND without destroying the bristles in doing so.
If you leave your brush sitting in water, for even under a minute, the tips of the bristles will become damaged and frayed. The more you do this the faster it happens. Now if this does happen, don’t toss your brush. It might not be in a healthy condition with those frayed bristles but there are techniques it can still be used for. The point is, when you want to keep your brushes healthy, don’t leave them soaking in water at all. You also NEVER want to store them, even dry, face down where the bristles are holding the brush up.
Instead, after each brush is used, wipe off excess paint on a paper towel, rinse in water until clean, and lay flat to dry. If you want to get them even cleaner AND condition them at the same time you can use a product like The Masters brush cleaner when you’re done painting for the day. I just lather the brushes up in warm water and rinse. If the paint is really in there and the brush is getting a bit crispy, you can leave the brush cleaner setting on the brush overnight (or for weeks at a time if you forget like I do).