Musaafirs intention changing before 15 days

Q:

1. If a person intends to stay for 15 days and perform full salah but leaves on the 14th day to a different city which is 10 miles away from the first city for 3 days and comes back to stay again in the same city for more than 10 days. Should be perform qasar salaah or full salaah in all the cities?

2. If a person intends to stay for 14 days in one city and performs qasar salaah but his stay extends by a day or two and then he leaves to a different city which is 10 miles away from the first city for 3 days and comes back to stay again in the same city for more than 10 days. Should he perform qasar salaah or full salaah in all the cities?