I have a bit of a love/hate relationship with this concept.I love the device for its consistent perfect performance. It has survived 2 years now of daily use on a pantry in a house of 7 kids. I calculate that as 72 billion uses.It is now in use on multiple closets as well.The hate comes from finding EVERY closet without this installed now has the light left on 100% of the time. The laziness this has stoked is unsurpassed.So, I am adding more by:-Turn on the light-Shut off the breaker switch (validate that the light is out)-Remove the switch from the gang box-Drill a hole through the door frame into the gang box using a long 3/8 drill bit-Run the wires on the “NC NO Door Window Contact Magnetic Reed Switch Alarm 3W 10-25mm https://www.amazon.com/dp/B00F0BQGP2/ref=cm_sw_r_cp_api_i_eGOlDb8PA2P43” to the box-Add a squirt of spray foam into the remaining hole space (optional -just seals the gang box better and holds the relay tighter into the door frame)-Install the relay (tight fit might require pushing wires back into the wall a little) — wiring diagrams online helped as did a meter (to find the proper relay wire) and basic knowledge of electrical wiring-Add a blank plate (you will get used to hitting the phantom switch on this plate for a while)-turn on the breaker switch-testOverall, install initially took about 45 minutes. After 3 installs, takes about 10 minutes.The delay to the switching is usually 1-2 seconds and can be a little annoying when you are in a rush, but the laziness it generates in return refills my impatience meter.The sound produced by the relay is almost exactly the sound my electric oven makes when the heating element clicks on.Kids still leave the door open and the light does not turn off until you close the door, but in my cases, this encourages them to deal with closure.enjoy