ATTQOYesterday:
I haven't fallen during a run...yet. It's probably inevitable. This is why I'm not a trail runner, though; I've always been very shy of going down steep hills where I don't have great traction, and there's a psychological barrier between me and going up or down a trail at any significant speed. I took a few spills off my bicycle back when that was my primary form of transportation, because that's just going to happen now and then--the worst was actually when the bike was stationary and I caught my leg on the rear wheel while trying to dismount. It took weeks to heal the skin on the hand I used to catch myself, and I was lucky that the bike coming down on my legs in that awkward position only resulted in a few scrapes. Also, it was the first day of grad school and I had to show up to my first class late, hand wrapped in paper towels from the bathroom.
I took a parkour course a few years ago mostly to learn how to tuck and roll (I have neither the physical fitness nor the bravery/foolhardiness needed for parkour). It's not bad once you learn it, but I'm so out of practice that I probably wouldn't think to do it if I was out running and fell (maybe that's something to work on again if I can find a floor space big enough to practice). The trick is to start by learning to launch yourself into a roll from a kneeling position; once you know that basic movement it's not so bad to translate it into a drop-and-roll from standing or near-standing. The other trick is to roll diagonally from one shoulder to the opposite hip to prevent stress on your neck; the way I was taught to think about it is that you're attempting to throw your head into the armpit opposite the shoulder you want to impact the ground.
ATTQOTD:
Honestly, at this point in my training if I miss it, I miss it and I move on. I haven't run for at least two weeks now, but this morning I finally got back out there and took an easy run. I'll dial back the distance on Saturday to gauge how much I've lost, if anything, then start ramping back up. On weeks when I know my schedule is going to forbid a run I try to work around it, but I've come to realize that there are limits and it's not worth driving myself insane or shorting myself on sleep to force it to work. There's always next week. I'm more inclined to just push the schedule back a week so I still keep the same progression without skipping over a distance goal.