I have had the Moto Metal Wheels M0961(similar to the picture minus the crome inserts) on the JK for 2 years now. I just noticed one of the front rims had developed cracks at the base of each spoke. Who knows how far away I was from riding with just spokes on the hub and the rim and the tire separating...

 

I'd suggest swapping them out immediately. Do you really need to know how long you have if your wheels are cracking?

 

Is it the cast actually cracking or could it be the finish? Assuming they're cast aluminum, they shouldn't crack. It either breaks into 2 or doesn't.

 

I never thought the MM rims are prone to cracking. Can you post a picture with the actual damage?

 

I tried taking a picture, but the hairline cracks around the base of each spoke are not really visible in the picture. Basically every spoke has a crescent of a hairline crack around its base. I did not x-ray the rim. Just pain logic: if there are cracks on all spokes and visible on the surface, guaranteed the metal fatigue is beyond normal underneath. I will probably replace all 5 rims with a completely different brand after the warranty on the first is approved.