Cold-related track misalignment
Torsion springs lose temper and snap more often in sustained cold, and steel track contracts just enough to throw rollers off alignment on the coldest mornings of the year. On a house built around 1968, you're also dealing with springs and cables that have likely been replaced once already by a previous owner, sometimes with a mismatched wind or a cable gauge that doesn't match the door weight - we find this more often than you'd think on homes of this exact age.