The traditional 2 handle control valves on bathtub were old and leaking and rather than repair them, we thought we would replace and upgrade to a single lever control since a tub surround was going to be installed. The contractor removed the old water control unit and placed the new one in exactly the same location so that when the finishing plate was added, it was touching the water spout. So now when you take a shower, you need to bend down to the spout level to adjust the temperature or flow. The wall was open, how much more effort was it to place the control valve at correct height.
The tub surround installer came minutes afterwards and finished up, sealing the fate of control valve replacement. Big learning for us, just because you hire a professional doesn't mean that they are and always check on each stage before you move on even when it is pretty simple.