Since beginning my airline career I've noticed something very annoying that doesn't seem to make any sense. I'd say Denver (KDEN) is the biggest offender when it comes to this, but almost the class B airports do it. If you ever try to depart Denver you'll notice that the Departure ATIS changes roughly five to six times per hour. We'll often pushback with information "L" and by the time we get to the runway, "P" is current, even when the weather is 10 and clear. What makes the problem worse is that it's not a normal human voice recording of the ATIS, but instead it's a crappy 1982 computer voice that takes about 90 seconds to spit out the whole thing that a human could do in 10-15 seconds. This means instead of doing important pre-takeoff checklists, briefings, etc while Taxiing, we have to monitor the ATIS frequency almost continuously. And of course, ground always has important instructions for us right when the ATIS recording starts, so we have to listen to the whole 90 second cycle twice just to get the weather, which rarely ever changes (they just change the ATIS letter identifier...) This also means we can't monitor our company frequency while taxiing which creates other issues. What is the story with this? For what possible reason could it be necessary need to change the ATIS Identifier so often on a 10 and clear day? Class D airports do it once per hour (unless the weather/runway changes) and it works just fine, why reinvent the wheel?