If your magnets or steel pickup elements are falling off often it may be because your drum head is dirty or they have not been correctly applied. The pickup element should last as long the drumhead itself. See Applying the the pickup element for the step-by-step process.
Here are some things to keep in mind when you are applying the pickup element to a drumhead:
Always use the positioner: don't separate the legs from the dot before applying the pickup element.
Don’t touch the adhesive side of the pickup element. The oils of your skin will weaken the adhesive.
If your drumhead is dirty, wipe down the application area with a damp towel (you can use rubbing alcohol or water). Dry the area thoroughly before applying the pickup element.
Don’t reapply a pickup element that has fallen off. It will probably fall off again.
It's best to let the adhesive on the pickup element fully cure for 24 hours before playing. However, if you have to play right after applying the pickup element (sometimes you just have to play!), you can put a small piece of tape over the pickup element to prevent it from flying off while you are playing.
Pickup elements are more likely to fall off if they come into contact with the sensor while you are playing. This only happens if the sensor is too close to the pickup elements (which is likely to be causing other problems, as well). Sensory Percussion works best on standard rims - stick saver hoops are at an angle that forces the sensor downwards too close to the pickup element.