One of ours broke a couple years back and they simply replaced both with no choice given. I think we got maybe 11 years out of it. Of course the guy rammed his ladder into my Chaparral hull by being careless. Luckily the ladder had a plastic top on it but then he used the boat trailer tounge as a ladder which pi$$ed me off too.
Think of it like a pair of shoes. Each one does the same amount of work, if one spring is old then the other is just as tired. Always good peace of mind to do them both. as for the oil- use a lightweight 3n1 or lightweight motor oil for lubrication. Cold weather is an enemy of torsion springs. when i was in the business of repairing overhead doors, I would work 70hrs a week in the winter compared to 20hrs in the summer.
