Boy, this thread is a roller coaster. You don't have to go that far back to see where I was getting beaten up for saying the Pax was a high maintenance device, now the majority seem to agree.
Cleaning, however, depends on how you use your Pax and what you put in it. Dry loads don't give off as much resin as weed that is still moist and sticky, so dry out your stash. If you tend to use it on high and finish the oven in one session, you probably won't get as much accumulated goo as someone who uses low temp and spaces out the hits, because when you do that, you create more opportunity for resin to form. Since the oven is always on when the light is green, when it sits around without being hit it's still producing vapour that can condense just where it can cause trouble. If you use it all day every day you'll obviously need to clean it more often than the weekend warrior. If you fail to take a clearing hit after you shut it down, you'll get more gumming.
Only you can tell how often to clean. Given the mouthpiece issue, you need to pay a little more attention to your Pax than your other devices. That doesn't necessarily mean you'll have to clean it more often, but it does mean you're better off checking to see if it needs cleaning after every session. As soon as you the mouthpiece starts to show signs of sticking, clean it. Keep the spring and retractor mechanism area clean. Try to keep your Pax upright until it cools down, and especially try to avoid letting it cool down inverted.
I've been told that the number of actual failures for the Pax is extremely low, especially considering how many of them are out there now. Most of the problems--and this includes most so-called temperature light issues--can be resolved and/or avoided with a little attention and proper cleaning.
Don't say I didn't warn you. Here is a nice bub that is being sold to FC member for $100 (no lettering) Worth checking out for sure, I may even get one, just because it's such a great price. 
