HD axle shafts are definitely on my list of to do projects. Had asked earlier, is the stock rubicon air locker sufficient for now or should I think about ARB lockers? Running 35s right now, plan on upping it to 37's with beadlocks at some point but that should be as far as that goes...
Running 35's, I would say that your factory locker will do just fine. It's when you get into 37's that you'll really start to see it's short comings. The internal components will start to crack and swell under the load and that will prevent it from working properly. Still, I would wait until you actually need to replace it.
Plus there's not a lot of desert out here on the east coast. Mostly trail riding, some mud and snow but honestly nothing very hard core
Even the most hard core rock gardens won't bend an axle housing the way bombing through the desert will. I ran my two of my JK's with just gussets and without any sleeves and only really started to see bending of the axle after I got coil overs. I know that Moochie ran his JK for years with sleeves for years but only started bending his axle after installing coil overs. It's just so hard not to drive a lot faster with them on and we have a lot of wide open desert to put them to the test on.