Plumbing:

• Buying a toilet?  Measure from the finished wall to the bolts.  That measurement is important to us.  Do you have a counter top over the toilet and if so, what height is it?  If you have carpet, make a note of the “footprint”.   Is there a door that will swing into the toilet?
• Buying a tub?  Tell us the measurements you have available.  If new tile or walls are going in, that measurement might change-let us know.  Let us know where the drain is.  Is the tub filler going on the wall or the deck?  If it is on the deck-give us the measurements available.
• Replacing a faucet?  Measure how far the holes are apart from each other and also measure how much space is there from the back splash and what is the measurement to the sink opening?
• If you are trying to replace a part, bring the old part in.  There are a bazillion options out there.  You trying to describe it to us is a pretty sure way to get something that doesn’t fit.