I had a good drag, anchored off Jewell Island near Portland this fall. My anchor watch has changed. I remember many nights walking around the boat looking through a hockey puck compass and jotting bearings onto a pad of paper(tedious). Now I use the Chartplotter every time I drop the hook(even calm, you never know). But if conditions are dicey, I'll set a distance alarm on the gps, and sleep in the saloon so I can scan the little screen without getting up.
Here's a typical comfortable "picture". The fat crescent is a short swing, about 15 knots of steady wind, during an overnight tide change close to a lee shore(I slept in the saloon this night off Harbor Island, Muscongus Bay). I leave the pointer at the anchor drop as a visual reference then keep track of the boats swing(black pointer). When a gust wakes you up, you watch the pointer,... The depth sounder adds another piece of data to watch and another alarm. This year, I used the ipad a few times in the veeberth to keep track of the boats position as well. Nice.
Back to Jewell, I got up about midnight to use the head(Jeremy is right,...) and scan the CP screen. What?. No crescent. I'd never seen what was on the screen in front of my eyes. There was a graceful pattern, like the path of a falling leaf, scalloping back and forth, and leading off the screen. What? I zoomed out to see what looked like directions for crocheting a long scrarf,...."Whoa, we're dragging!!!"
You know the rest. I got the engine started and very quickly raised anchor, without the windlass, and I was off to re-anchor. I had "anchored" along the edge in shallower water(too many boats at Jewell, even in September) on washed rock when I arrived late afternoon. I did "set" the hook earlier, but maybe not the full power I should have. It was at higher tide when scope reduced that the dragging started.
I need a good anchor drag every few years as I become complacent after a while.