There's no one-size-fits-all answer to this question, as the decision of whether or not to pay off a 6 year old collection will depend on a variety of factors, including your current financial situation, the amount of the collection, and the terms of the original agreement. However, in general, it is usually advisable to pay off any outstanding debts, including collections, as soon as possible in order to avoid any negative consequences that may come with having a bad credit score.