Loose hair can collect in your drains and pipes, causing hair clogs that will prevent your tub from draining properly. If you or members of your household have long hair or lots of hair, it may be necessary for you to prevent hair from going down the tub drain in order to avoid costly plumbing problems in the future.
There are a number of specially designed drain traps and covers that you can purchase for your tub to keep hair from going down the drain. These covers create a barrier over the drain that will allow water to drain but will catch hair and other debris before it can also go down the drain to clog your pipes. These covers fit over or in your drain, much like sink strainers for your kitchen sink, and can be removed and cleaned as necessary. Some of these are designed for tubs with pop-up drain plugs that can't be removed.
An inexpensive kitchen sink strainer that fits larger drains may be able to be used on your tub, depending on your drain design. You want a strainer that is wire mesh with small, tight openings that are designed to keep hair and other debris from going down the drain. This will only work if you have a tub with a drain that goes straight down and does not have a permanently installed plug.
You can make a hair trap at home if you have a small section of very tightly woven mesh fabric or wire with small openings on hand. Cut the mesh so it is slightly larger than the drain opening. Hot-glue a circle of pennies or other small weights around the edge of the mesh, then place it over the drain. If your weights are heavy enough, they will hold the mesh over the drain while you shower, and the mesh will catch hair that is sucked into the drain.
Some hair is going to fall out in the shower while you are washing and conditioning, but there are some things you can do to keep hair out of your drains to start with. Brush your hair thoroughly before entering the shower. When loose hair collects on your fingers while shampooing and conditioning, set it on a shelf or the edge of the tub instead of dropping it into the water. If you prevent as much hair from entering the tub drain as possible, use a strainer to keep the rest out and then regularly use a cleaning or clog-preventing product on your drains, you should not have a clogging problem.