The evening before Baby Girl came, I made such a rookie mistake. A veteran foster parent once told me that because of the unpredictably of foster care you should never count on (and thus prepare the room) a child coming to your home until they actually walk through the door and never count on them leaving (and thus fully packing up the room) until they walk out the door. I was 100% unsuccessful on this with Baby Girl and her room.
There have been many times in the past two years that I haven't done this. I have heard "for sure" kids are coming, only to prepare the room, discuss the situation with my family and my current kids, buy supplies, etc. Only to hear later on that they will not be coming for one reason or another and then having to retract all those conversations and put the house back to normal.
Before Baby Girl came, I not only bought a crib, I also put it together, rearranged my room for it to fit, I also...
bought diapers, formula, washed the right clothes and put them away in her room.
So glad she came. Now all these things are being put to good use instead of me trying to figure out what to do with an empty crib in my room.