Foul weather gear isn't built to last forever. If it was it would be as stiff as a board and wouldn't breathe at all. Actually it’d be a lot like foul weather gear 30 years ago. Fortunately technology has come a long way since then and now fabrics are breathable (a miraculous concept) and are significantly thinner than but just as waterproof as materials that came before it.
High quality garments can still last 5-10 years with good care. You need to rinse it out with fresh water frequently, especially if you sail in salt water. At least once a year I also clean and waterproof my well-loved garments with McNett’s Synthetic Fabric Cleaner.
Most garments have waterproof material either built into the fabric or coating the inside of the fabric. Most all jackets will also have a DWR coating (durable water repellent) on the exterior fabric which augments the garment’s inherent waterproof-ness.
This DWR wears off after time but you can re-apply DWR with McNett’s Durable Waterproofing. McNett makes a wash-in waterproofing but I prefer the spray on version personally.
These two McNett products are specifically engineered for use on Gore-Tex or other similar 3-layer fabrics. You can use them on 2-layer fabrics but it’s important to keep in mind the 2-layer fabrics are typically less durable and should not ever be put into a drying machine for whatever reason.
Anyway without any (more) further adieu watch the video to see how to use these two products: