How many times have I walked into people's homes and heard them say, "We need new tiles around it, but we'll keep the tub." I have to laugh, because why would you keep the tub, put up a new wall with new tiles, and then have to take it all down again in a few years when the tub needs to be replaced? It just doesn't make sense. In fact, by far the most common mistake that I see in bathroom renos is the quick tub, toilet, and sink replacement.
What happens is that the homeowner goes to a bathroom place or to a bathroom/kitchen store. There are tons of them, and they are well-known, big-name companies, where the goal is to get you in, sell you a bunch of merchandise, and get you out again fast, before you've had a chance to really think things through. They make it sound as if -- and I love this: It's the same as when you're buying a car -- you can get a new bathroom from $6,395. Yes, everything is "from," but nothing is ever actually sold at that price. It's always twice the cost of "from."
In most cases, you can't just do a quick fix and leave it at that. It's not worth your money, especially if you get sold on one of these "from" packages. Simply replacing the tub and tile, toilet, sink, and cabinets is not going to solve your problems. If you're going to stay in the house, all you'll have achieved is putting off the work (such as proper plumbing and electrical, getting rid of mould, and proper waterproofing) that is going to have to be done eventually. And later, to do the job right, your contractor is going to have to pull apart that quick fix.
Let me give you an example of what not to do. I had a couple call me one time and say they wanted a new bathroom. I went in and I could tell right away that it had been done before. I took a look at it and decided to do a complete gut. As I gutted, I discovered this was the third time the bathroom had been renovated. I was the fourth guy in there, and everyone else had covered over what had been there before them: drywall over tile over drywall. It was a complete cover-up, with mould galore. There is no such thing as a quick job.