I wear all kinds of old stuff on trails: pants, sweat, whatever I have clean at the moment. In fact I use it all in ring too (especially in winter when it's cold). I use breeches mostly when I feel like it (not every ride) and for lessons (and shows of course).
P.S. I don't ride in jeans: they are too restricting.
"Life isn't about waiting for the storm to pass: it's about learning to dance in the rain..."
"When we are no longer able to change a situation - we are challenged to change ourselves."
"How people treat you is their karma; how you react is yours."