A door and track system installed around 1970 was engineered for a different set of expectations than what's sold today. Torsion springs from that era often ran on standardized shaft sizes that later manufacturers changed, so a spring you buy off a generic rack may be close but not correct, and installing a slightly wrong spring on an older shaft is how cables jump track. Openers from a 1970s install, if they haven't been replaced, are also long past the design life of any chain or belt drive - the original units simply weren't built with today's cycle counts in mind. Given the area sits in a cold, severe winter climate, older weatherstripping and worn bottom seals let more cold air through than they did new, and that shows up as ice buildup on the track in a hard freeze. None of this means every door here is a problem. It means the fix that's right for a house built in 1995 closer to town often isn't the fix that's right for a house built in 1970 out here, and we price the job based on what we find, not a standard sheet.