I remember when we all had the 713 area code. Then they did the strange 'overlay' thing and basically anything outside the loop became 281. We had to inform family, friends, work, etc. about our new home phone number. Businesses had to change their letterheads from 713 to 281. Area codes 832 and 346 were added later and i saw on my news feed that they are going to add another one because of the 'surge' of people who are getting cell phones.
I'm glad they don't do the overlay anymore when they add new area codes.