Of course, getting a tablet to last longer between charges takes a little effort on your part, as well as a willingness to accept a few connectivity and performance trade-offs, which we address in this slideshow.
A metal base plate protects the bottom sides of your door from dings, scratches and scuffs. Wood door base plates come in two types: adhesive-backed and screw-on. A screw-on base plate requires putting holes in your door, while an adhesive-backed one does not.
IF it happens to be an undrilled solid plate steel door with 1/8-1/4 plate on both faces, like a heavy duty high security door or converted warehouse loft heavy sliding door, then more like an hour and $150-250 total charge as above, because it takes a long time with a carbide or diamond bit to cut through the steel.