There are all kinds of home repairs that home owners can do themselves, Caulking tubs and showers are pretty simple to do. Takes just a little time and can protect you from expensive water damage in and around your tub or shower.
Water leaking around these areas can cause damage to the flooring system, meaning sub floor, Floor joist. Replacing floor joist is no easy task , The shower or tub may need to be removed in order to do the floor repair, Later to be re installed and plumbing connections made.PVC piping is always the best material to use on most plumbing systems, Its easy to work with and less expensive than Metal piping or Galvanized piping. If you need a replacement tub or Shower insert you can pick any one of those up at your local Hardware, Home Depot or Lowes home improvement store. You may want to call a License contractor in to either do that part of the home repair or have him look at your work, or a general Handyman if you feel you are over your head. A good handyman can be a huge help. a Licences plumber will be required if you move any plumbing from its original positions.
Always make sure you have the right tools, Wrenches, Teflon tape, Caulking ( Dap 230 is a good quality caulk ), plumbing fittings ect.
So you can see why it is important to make sure your tub and shower are always sealed and water tight. Also make sure that your shower doors are in good condition.