I stopped stretching before rides after I read some articles posted back in 2013-14 how it was bad for muscles/ligaments. Seemed counter-intuitive but "science" you know? I was in my late 20s so it didn't really seem to matter
I've always sorta had some, but this year especially I started experiencing issues I suspected were related to poor off-bike posture. I'm now in my mid-30s. I started doing a 30-second routine that includes a few different stretches for calves/back/pelvis/hamstrings. Stretch and hold for 30 seconds and then move to next stretch. Takes about 10 minutes and helps serve as a warm-up for my ride. Riding issues went away and I feel much better during my ride - including a 200 mile ride I did last weekend. Went much better than previously in part I suspect due to stretching heavily beforehand as well as during the ride itself.
For long distance riding I try to stretch and massage during the ride whenever I can, including coasting downhills. It makes a huge difference, something as simple as massaging forearms and hands a few times over the course of the first 6-8 hours can make things much more comfortable when hour 11-12 roll around.
So I like stretching before a ride, seems to work well for me. I also like to stretch on non-riding days when I wake-up in the morning. Helps get my body awake and seems to cut down on recovery time and delayed onset muscle soreness from very long or hard rides. Try it out, it'll be obvious before too long if it works for you or not.