When I was a kid, we only went to homes that were *decorated* and had lights on. Probably pretty smart move in an immigrant-heavy area. Nothing wrong with apartment complexes, either, as long as you only go up to decorated doors. And they were quick to get around (more units/area than single family home neighborhoods). Past couple years I've lived in a shady-ish neighborhood, and although we had tons of kids I never saw trick or treaters. We also didn't decorate. In a new place (city) this year, hoping someone will come by...we're off a large non-residential street, though, a dead end for trick or treaters. So probably not many.
It's totally fine to hand out candy yourself. IMO, it's also fine to judge by age and/or costume, although a friend posted something on FB about kids without costumes possibly having sensory sensitivity, or kids who don't talk having a developmental delay. That seems like a good thing to be aware of... I would totally give a 10yo with an awesome homemade costume an extra big handful and a costume-less teen just one.
Actually, when we got up into the 12-14 age range (where some still wanted to ToT and others felt awkward), my friends and I started making up and singing "Halloween carols," such as "the people outside are frightful" to the tune of "let it snow". Big success. We also did always make/design our own costumes at that point.