While many of the currently available handgun optics solutions were developed for the competition market, there are also solutions appropriate for home defense.
When it comes to home defense, I prefer sighting options that are already turned on and ready to go, but that’s just my preference. A couple of good solutions come to mind.
Trijicon’s RMR (Ruggedized Miniature Reflex) sight is available in a dual-illuminated configuration. A fiber-optic tape across the top gathers light to illuminate the aiming point in daylight conditions, while a tritium lamp insert provides just enough light to power the reticle in low light and dark environments. No switches to remember and no batteries to run dry. It’s always on and ready for use.
Another viable option is to recommend a long-life battery-powered product. I’ve used a number of Aimpoint optics, and the Micro H1, T1, and T2 series are perfect for handgun use. Aimpoint offers mount adapters that make use of the rear sight dovetail in some popular handguns, so the small tubular red dot sight mounts without any drilling or tapping of the pistol’s slide.
I’ve used this configuration on Glocks with great success. An added bonus is that the tube configuration eliminates the problem of “finding the dot;” it’s a crude aiming solution in its own right. While these sights are battery-powered, they’re designed to run for years at a time, so you can leave it on and change the batteries every New Year’s just to be on the safe side.