One of the reasons that mechanics are very conservative on this point or reticent to answer at all is that the bearings in a clicking CV joint have already failed. In the worst case a clicking axle can come apart, stranding the vehicle and potentially doing collateral damage as a broken axle spins. This writer had a Caravan towed in years ago with a broken axle that had beaten a hole through the transmission case, for instance. Therefore, it’s difficult to find a mechanic who will tell you a clicking axle is ok to drive on. But, liability concerns aside, it’s not uncommon to see a CV boot start to leak grease, and to be ok for a few thousand miles before the joint starts to make noise. And then it’s not uncommon to see that axle get very slowly and progressively louder over 10,000 miles or so, without breaking, as long as the driver is easy on it. It’s still a problem best taken care of when it is noticed, but it is possible to nurse things along for awhile.