Possession date
The closing date may be different from the possession date.
The closing date is the day title legally changes hands. When the buyer gets possesion of the property is negotiable.
It is customary in our area in Southern California to give the seller an extra 1-3 days to move out completely. Sometimes the seller try to negotiate up to 5-7 days, but I think that is stretching it. Basically, they are asking for the buyer to give them that many days of free rent, in the meanwhile, the buyer has already started making payments on the house. A few days does not seem to matter much, but if your mortgage is $3000 a month, that’s $100 a day you are paying. Five days is worth $500.
Ideally, the buyer gets possession on the day escrow closes. The seller is completely moved out, and all keys and garage openers are handed over. But it doesn’t hurt to allow a couple of days for the seller to clear out. Any more than that the buyer can ask to be compensated per diem by the seller.