Usually you have to replace the wood that they created their hive on since the bees will return to the same location again.

Not really, but I do wash it with bleach to kill the smell. Of course, sealing up the area tightly is a must as well.

You DEFINITELY want to make sure that the area was cleaned out properly and that it was bee-proofed. Texased69 is absolutely correct that if not done properly, the area will attract another hive. The smell may also attract rodents and other animals who will eat through a poor proofing job. There are a number of companies that will do this type of bee removal in Houston for you, but if they gave you a year warranty, they probably did the job correctly (or if they didn't, they'll be back for free!).