Salt and sand are the worst enemies of sails or lines. Get in the habit of doing these things to get the longest life out of your gear.
1 - Rinse your kite with fresh water at very gentle pressures. Knocks all the sand off, cleans all the salt out. Bridles too. Both will eventually eat your stuff, but you can delay that with good cleaning habits. Got a Rev 1 from about 1998 in my bag in great condition.
2 - Rinse your lines regularly. No need to unwind, it does help to wind loosely though. Just put winder and lines in a tub big enough to hold them. Maybe add a few drops of detergent to the water. Place on a towel to dry after the soak. You'll be surprised to see how much sand comes out of them. And the soaking dissolves the salt crystals and prevents build up. Lines do wear out eventually. As a team flier, I go though almost 2 sets every year. Crossing lines is very wearing.
3 - Swap your lines end to end. If you have always used your lines in one direction, try turning them around. The wear spot from crossing will happen in a different place. Never tried the Sewer's Aid myself, sorry.
You can remove the rings on the handles and make your own snag-less ones. Use an 8-10 wallboard anchor and screw to replace them. Works really well and is a cheap alternative to buying new handles. That video walks you through the job, should take around a hour to do a set, less if you're handy with tools. Holds up for a very long time.