Briefly, the offset smoker utilizes a horizontal steel cylinder with a chimney on one end and a fire box on the other. Heat is generated in a separate area - away from the food and is evenly delivered to the food and allowed to leave at the other end via the chimney. This is slow cooking at its finest. They can also be expected to last 20 years or more with proper care and maintenance. Brick pits work similarly.
Heat is placed at one end and the meat is at the other.
The chimney is at the end opposite the heat source. If you do the work yourself, AND WE DO CALL IT WORK , the costs can be more reasonable. On the other hand if you want someone else to do the work, dig down deep in the 'ole wallet and be ready to pay the piper. Depending upon the quality of construction, they can expected to last 10 to 20 years plus, again with proper care and maintenance. An additional concern we have with brick is that they will crack and break and become less attractive.