I have had problems with them curling around the line/jig head if the water is below 55-60 degrees. For whatever reason, I haven’t used then much early or later when the water temps are that low so I don’t remember exactly what the temp was.
I’m sure they’d still be great now! Not sure what the water temps are but the lake I went fishing on yesterday had some leeches swimming around in the shallows. I guess, I would still be throwing them on a jig, but I always throw crawlers with my jigs.
I generally fish with them until can’t get them or I switch to the short rods. no matter time of year always dip them in lake right away to get used to temperature before they twist curl and tie my setup into a knot with that blasted leech sex juice they get all over the line.