The most common mistake on a 1968-era door is matching a panel for fit but not for gauge. A lighter-gauge replacement panel bolted next to an original heavier panel flexes differently in wind and cold, and that mismatch stresses the hinges and rollers around it faster than a uniform door would.
The second issue is the track. If the panel swap isn't paired with a track check, a slightly warped original track - common after decades of freeze-thaw movement in this climate - can bind a brand-new panel the same way it bound the old one. We check track alignment on every panel job for that reason, not as an upsell.
One honest limitation: if the door is a true discontinued profile with no manufacturer match available, we won't pretend we can fabricate an exact panel. In that case replacement of the full door is the straighter, more honest path, even if it's not the answer you were hoping for.