Just keep it clean and always in the storage solution when not in use and it will extend the life and accuracy. And don't use it in Pure distilled or RO Water, it screws it up fairly quick. Letting the bulb dry out is also bad too, will lead to bad readings and calibration won't even fix it. Put a piece of sponge in the cap and soak it with storage solution, this will keep the ph bulb from drying out when not in use and you will use way less storage solution, just put the cap on pen and sit it upright until next use......I like to rinse off the probe under tap water before I use it in my feed water So the storage solution doesn't react with anything in my feed.