"what the carpet layers will do to prep. Will they mop the subfloors or just lay the carpet as is?"

Unlikely, especially if it is not called out in a contract.

Funny, we just got an email from our builder on this subject. He said the final cleaning includes cleaning finished and unfinished space i.e. mechanical rooms and the garage (wiping down mechanicals and mopping those floors). The cleaning crew also removes all the stickers left on windows, appliances, removes the plastic from french doors, etc), wipes down and clean out all cabinets, cleans all of the windows, basically every nook and cranny in the house gets cleaned. He said he typically pays $.18 per sq ft. We're in near Chicago suburbs, I know each are of country can differ a bit when it comes to pricing. I hope this helps a bit!

I would just like to know if I should sign up for the final "clean"

It depends how much the savings are worth to you.

jhs2010! Thank you...that is what I needed to know! Our final clean was bid out at 15 cents/sqft. The part I am dreading is cleaning the garage floors & all the windows. The sheetrockers left the biggest mess. Maybe it could have been worse as I have nothing to compare it to...

"The sheetrockers left the biggest mess."

Finishing drywall is messy work.

Some of the mud always ends up on the floor, and letting it dry before removing is the best way to clean it up.

It is much easier to go around with an ice scraper and pup up the dry pieces than smearing it all over trying to clean it up before it hardens.

Some dust and sawdust on the floor makes it even easier to clean up after finishing drywall.
This is one time you want a dirty floor.

That is where we made one of our mistakes is not getting the cleanup in the written contract. Especially the drywall. The wood part wasn't too bad as we had a fireplace and cut up most of the wood to use.

Yes, I actually read on a thread here that dust on the floor makes it easier to clean up the sheetrock mud. I bought a scaper on a pole and found it easier to turn the blade over and scrape that way vs trying to get up under the dried mud. Cleaning up after the trim guys was easy...we'll see what the painters leave! A friend told me that their clean up crew didn't always keep up and it caused delays. They wound up having to pay for the service and then wound up doing a lot of it themselves...something to think about...