dont you all find your lets call it the core area of the shorts top of the thighs, gets a bit chilled when its cold if you are just wearing the same kinds of shorts you do in summer ?
I mean for me knee warmers are great keep my creaking knees warm, I use them in that tricky crossover period when its still quite mild at times but might be chilly in bits early morning or late evening, so summer level shorts are fine.
Ive then got fleecy 3/4s, but theres literally only a couple of weeks per year in spring/autumn they work as an option, because it either rapidly becomes too cold and your lower calf and achilles start aching as a result, or its too warm and your back to knee warmers/shorts. again.
I do have a pair of leg warmers,but Ive only used them once or twice at most. if its cold enough for leg warmers, its cold enough for tights. which then also keep that core area warmer and free of wind chill effects, and Ive never been on a ride with that wide enough of a temperature range to bother changing that view.