Taking care of your tools is important. I often forget that many people will buy a great brush because they've been told, truthfully, that a good quality tool is part of what makes it easy to do a great job with your makeup, but then get sent home with no idea how to care for it.

Storage

Most makeup brushes come in a plastic sleeve, usually resealable. Resist the urge to store your brushes in these since it's not possible to clean them, and thus they just get the brush dirty again every time it goes in. This is the same reason I tend to avoid retractable brushes.

I use a cup on my makeup table to store my personal brushes. They don't get cleaned daily because they're only being used on me, and this keeps them aired out and means they don't get powder or cream all over whatever I'm storing them in. It's also easy for me to look at and grab whatever I need.

For transporting brushes I use a brush roll. I like ones that are washable fabric, because when they need it they can just go in the laundry.

Cleaning

If you use them daily, giving your brushes a good cleaning every 2-4 weeks will keep them in great shape. You need warm running water, cheap shampoo, a towel, paper towels, enough spare counter space to leave the brushes laid flat overnight, as well as 99% rubbing alcohol and and a small glass (if you have synthetic brushes).

The goal is to never get anything but the bristles wet, and not to get any liquid into the ferrule, which is the metal part between the bristles and the handle. There is glue inside the ferrule, and repeated wetting can break it down over time. Also, you should only ever clean brushes by moving them back and forth, not in a circle, because this helps keep the bristles from shedding.

First, lay your towel out at the edge of the counter.

Sort them out your synthetic brushes (these are generally your liquid or cream foundation and lipstick brushes). Pour enough rubbing alcohol into the small glass to cover their bristles but not enough that it soaks the ferrule. Let them soak at least five minutes, then wipe the makeup off them with a paper towel until no more comes off and lay them flat on the towel with the bristles hanging off the edge of the counter not touching anything until they are dry.

Next get your natural bristle brushes over by the sink. Run the water at a nice comfy temperature, your hands with be under it a lot. Let the water run across your palm, and wet your natural bristle brush by rubbing it back and forth (not in circles) across your palm. Add a drop of shampoo and work it into the bristles, still rubbing it only back and forth, then rinse it the same way you wet it. Squeeze the water out gently, and if suds come out, rinse until they don't. Shape the brush with your fingers after squeezing out the water, and lay it out to dry just like the synthetic ones. Never leave brushes standing in a glass to dry. Once dry, rub the brush on a towel to fluff it back up.