If you have shower tub, you may be confused to let it go in case you want to add the shower in your bathroom. However compared to showers, which you have to change occasionally, the shower tub can last yearner after the installation. If you have distinct to remove the shower tub, you will remain with a hole and you need to do more retiling on the floor and on the walls which can be expensive. When you remove the tub, also you will be required to disturb the plumbing which can cause the shower to drain poorly. Instead of removing the shower tub, you can consider to install the shower besides it, since it is cost effective.