Mine are numbered and they come off after each trip. I store them in the small floor compartment by the rear door.
I also keep the transmission tow/untow instructions there also. I know the procedure but reading the steps makes me feel better.
I printed the instructions and lamenated it. Hook up on one side, unhook on the other.
I also painted the mh sensors white per tireminder cs rep. I had one sensor make some funny readings when i checked them prior to travelling. The sun was beating down on the senson and reflecting off the rim. The sensor was super hot.
I now also bring my tire covers and use them on camping day
If you are going to leave the sensors on the toad - be sure they are the correct metal... There are special sensors if the vehicle has an onboard TPMS (valve stems are different metal which can react with the sensor metal over time...)
I typically take off the toad when not traveling with it - but even extended trips (3-4 months), I've just left them on.