#1 Lesson is be flexible, come armed with clear goals/ a plan /a budget /and cash. When things need to change (and they will) roll with it. It is not the Sistine chapel.
#2 Lesson is you will find mold. If you are tearing out an old bathroom, be prepared for mold remediation. Absolutely everything has to be spore free before you button those walls back up. You may need to replace studs, clean & seal concrete etc...Budget appropriately, then add 25-50% more $ and time for surprises you WILL find behind the walls.
#3 Lesson is to document document document. How many bathrooms will you renovate in your lifetime? Enjoy the process and take lots of pictures, keep a journal of everything. It is rare, but if things go pear shaped you already have a record.
Q
This is an interesting take with the position of the tub and the shower. That's a good take for a small bathroom.
Q