Is there a reason you want to wait? If you know you want crown molding it will be much easier to do during the build.

If it were me, I’d just get it all done before moving in. Yes, you’ll more than likely overpay, but who wants the hassle?

Have it done now. If you wait until you've moved in, then you're going to have to move furniture and be prepared for a bit of dust from filled nail holes.

I actually overlooked crown molding and didn't choose it during the initial contract and now I feel like I should have chosen the package. House will be done in Oct but I can still pay a fee for change of order and add it in. Just wondering if it's worth paying the fee to get it done and over with or wait until closing and find someone to do it afterwards

I was planning on getting it done after house is closed and before we move in but I believe I will start the process of adding it in. Thank you!

OK am going to call the agent now. Thank you so much everyone!!

It comes down to dollars and cents.
Also apples v apples.
As for convenience...The builder will install it before the house is painted and you will have it once and done.
Sometimes because 'life happens' those kinds of things slip through the cracks and never do get done at a later time.
All the best