A:Answer Hi Jim,
Thanks for all these great questions! Just in case that consultant wasn't able to answer for you:
SimpliSafe's Entry Sensors work by detecting a magnet, so placing it on top of a steel or iron door might affect its function. But as long as it's shielded, it should work as intended.
Also, all of the sensors for this system (the SimpliSafe Original) can operate up to 400ft away in an open field, though in a real world environment we would recommend that you keep them within 100-150ft of the Base Station.
Finally, the Sensors all have an expected battery life of 3-5 years!