People who are selling their home in order to buy another frequently put a "coinciding settlements" clause into their contract offer on the new home. One reason for doing this is so they can move from one home to the other at the same time.
Coinciding Moving Day?
One reason people want coinciding settlements is so they can move out of one house and into the other the same day. Sometimes this works out. Sometimes not. If it doesn't work out, don't freak out.
For example, if the house you're buying is a new one, it may not be completed and have an occupancy permit by the date specified. Are you going to risk losing the sale of your old home by insisting that settlement be delayed? Not if you're smart and you really want to make this change. You might explore delaying settlement, or the option of a "lease back" period. If those ideas don't fly, it's time to cope.
Depending on your budget and the length of time between moving out of your old home and moving into your new one, you could:
1) Have the moving company store your furniture and household goods, or
2) Rent a "smart box," pack your household items into it, and leave it parked in front of your old home, or park it in front of your new one (depending on who grants permission), or
3) Store your things in the basement or garage of your new home (with permission), or
4) Rent a storage unit by the month, or
5) Store your things in the basement or garage of a relative or friend, AND
A) Stay in a hotel or motel for a few nights, or
B) Stay in an extended-stay hotel or motel suite, or
C) Stay with family or friends, or
D) Go camping, or
E) Some combination of the above.
The point is to act like a mature adult. Be flexible. You're making a big change. The chances it'll go off without a hitch are slim. Keep things in perspective. Practice creative problem solving. You'll be proud of yourself and have a smile on your face when moving day comes.