The #1 leading cause of water damage in bathrooms is faulty tub surrounds. When you finally decided to replace the leaky surround you may consider a glue on surround, a fiberglass insert, tile or new tub altogether. There may be some rot and you should replace the plumbing as the old copper lines wear thin and are prone to failing. 

Well once you have gone that far into the project you might as well replace the toilet, sink/vanity, drywall, insulation, vaporbarrier, window, tile the floor and why not have some in-floor heat...

 

Or Maybe.... Call a professional so you can plan all of it in advance.

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