There are several factors to consider when evaluating the condition of the sail. Stains and dirt are probably the least important, stitching and cloth condition are much more important. Around here
@DrJudyB is the person to listen to.
The first thing I noticed about the sails is how soft the cloth seems to be. A new sail will have stiffer cloth and fewer wrinkles. Sailcloth is usually coated to add stiffness, reduce stretching and provide some UV protection. Over time and use, the cloth stretches and the sail shape changes which affects the sails efficiency. Sails that get stretched out, or bagged out in the sailing vernacular, reduce the ability to sail to windward and cause the boat to heel more. That's real important if you are racing, and kind of important for just daysailing. Boats that sail well are more fun to sail. A good sail helps to make a boat sail well.
The mainsail leech may or may not be repairable. It depends on the condition of the cloth and whether it can withstand more stitching. UV exposure has probably caused the thread to rot. If there is a local sailmaker you can take the sail to the loft and they will be better able to advise you of your options. You should consider the repair cost vs replacement cost. No point in sending good money after bad.
The issue with the jib is the same. UV exposure rotted the thread. This repair is a better choice for repair tape, but it will be a temporary repair.
Your plan to start saving for a new mainsail is a good one. Geographically, you're in a good location, not far from LI Sound or the Boston area. I'd look for a smaller loft to avoid paying a premium for a big name sail from North, Quantum, Doyle, etc. Now is a good time to shop for a sail as lofts often give discounts during the winter.
Enjoy the winter planning for next summer's sailing season.
