If you keep the connection point where the cable enters the stainless probe dry, they last for a long time. I think the probes may also have an upper temp limit that can damage them, but I don't remember off hand what that is for the Maverick. The upper temp limit is probably more of a problem on a direct cooking BBQ grill than in a smoker just due to the higher direct fire temps.
I have been using an older version of the Maverick in my kitchen roughly 4-5 times per week for the past 4-5 years. Only had to replace the probe one time in the first year, and that was my fault for washing it wrong (soaked it to get some crud off before I knew to keep the connection dry).