In much the same way as you service your boat's engine each year, it's a good idea to drop sails off at your local sail loft to get them checked over during the off season. Many sail lofts will carefully check over sails, repair any tears or worn stitching, and launder them so they'll be ready for spring. Reputable lofts will also report back on the overall condition of the sail(s) and offer advice when it's time for replacement.
Most cruising sails are made from Dacron, a stable fabric available at a reasonable cost that stands up well to UV rays and regular handling. Other materials like carbon fiber, Dyneema, Spectra, and Kevlar are often used in racing sails for those wanting the best performance, but these materials come at a cost many times that of a comparably sized Dacron sail. Manufacturing high-tech sails requires specialized equipment, one reason for the increased costs.
As any old sailor knows, worn and tired sails stretch and often have too much bag in them, which in turn leads to excessive heeling, increased weather helm, and slower speeds.
Just as the time comes when a boat's engine needs replacing, there's also a time for new sails. To the uninitiated, it's easy to think of sails as merely swaths of triangular fabric, but there's so much more to their magic.
Sails are carefully constructed of multiple sections of fabric, which for main and genoa at least, give an airfoil shape that, when seen in cross-section, is very similar to the form of an airplane wing. Except when sailing dead downwind, that airfoil shape is crucial for creating lift and driving the boat forward.
In terms of sailing performance, a new suit of sails is probably one of the best upgrades that you can give your boat," says Roger Cook, a retired sailmaker from Maine. "Because sails wear gradually, often the decrease in performance is not noticed. It's only when owners get new sails that they become aware just how poorly their boat was sailing."