This is a tiny guest bath redo. Took the tub and shower surround out and replaced with tiled walk-in shower. Painted the walls and vanity and replaced the hardware in both the shower and vanity. Replaced toilet. We kept the existing tile floor to save on budget so the transition from shower floor had to make sense while trying to keep to a vintage look.
And here is the learning: Many times you can save on your budget by keeping some of what is already there. In this case the flooring was not in bad shape and it was pretty neutral so we opted to keep it. Many times trying to save (especially with tile) turns into a headache because tiles break and replacing pieces can be more difficult than replacing an entire floor.
This is also true with plumbing and hardware. A new Delta shower faucet will not work with a Moen valve so a little investigating ahead of time is always a good idea. On the other side of the coin, painting a perfectly good vanity is a great cost saver especially if it functions fine and it’s in a bathroom that will not get a lot of use anyway.
So here is my advice: If you are a “do-it-yourselfer” find out what type of faucet is already there before you go searching for a replacement, it will save you aggravation down the road; and believe me, plumbing is an aggravating undertaking even on a good day. If you are hiring someone, ask them what type of faucet you should get and if the valve is good enough to re-use.
If you plan to do your own tile I would suspect that buying an extra 30-50 sq ft will not break the bank. If you are having it done ask your tile person how much it would be to do the entire floor as opposed to just part of it, you may be surprised that the difference is not that significant and it is well worth it for you to go ahead and get it all done at once.