Not necessarily. You can soak it in calibration fluids for a couple days and they come back there is articles written about it.
They told me this when I spoke to the people at Neptune. They said to leave it over night in the fluid. You should also keep the ORP probe wet as well. It's a good idea to keep the little caps that they send with the probes and if you ever take them out of the water for a long period of time just make sure theres a bit of saltwater in them.