Here's the honest part. Springs on 2003-era doors are old enough now to be near the end of their fatigue life, and this whole region sits in a severe cold band that stiffens spring steel every winter - that combination means a spring that looks fine in October can snap on the first hard freeze. When that happens on a double door, we almost always recommend replacing both springs even if only one broke, because the second one is on the same clock and a mismatched pair throws the door off balance. We also won't tell you a spring repair will fix a door that's actually failing for a different reason - bent track, a worn opener gear, a panel that's racked from years of one-sided lifting. If we get on site and the spring turns out to be the symptom rather than the cause, we'll say so before we start swinging a wrench, not after you've paid for parts that don't solve the problem.