I'm not all that knowledgeable about sails but, when I bought my boat new it came with Neil Pride Sails and I did a lot of trailer sailing, so I never had a sail cover. In time, my sails lost their stiffness and got thin and baggy. I got caught out in a squall one day motoring across the bay. I knew it was coming and I neglected to head into the wind. When it did hit, it hit from behind and tore a large hole in my furled sail. This was back in 1992 or 93 that this happened. So I had some new sails made, but this time I was determined to buy a sail cover and take good care of them, which I've done through the years. At the end of September this past year, my Mainsail got caught in one of my spreaders on an extremely windy day, and the sail received a large tear. I wasn't sure whether my sail was terminal or if it could be repaired, so I brought it to the sail maker who originally made it. He told me that the sail was sun rotted and that he could repair it, but couldn't guarantee the repair, but he would gladly make me another sail for about $1500. So I decided to get a second opinion as my Mainsail, although it's a little dirty, and the leach near the boom is a little frayed from the topping lift, the sail is still as stiff as the day I bought it, and is not stretched out. The guy at North Sails, pinched the material a little bit, and tried to rip it and it wouldn't rip. Then he said that the sail can be repaired by replacing a panel and making a new batten pocket. He also suggested that the pockets be reinforced with round patches at the end of each pocket. So I told him to go ahead and do the job. I'm sure that I could have had a sail made for between $500 and $800 somewhere, but having known that I've taken care of this sail through the years, this is the call that I made. You will probably have to make the call yourself, or take it to a couple of sail makers like I did. If your sail is thin, soft, and baggy, and can tear easy, you may have to bite the bullet and spring for a new sail. Luckily, my sail got torn at the end of the season, but I feel partially responsible because I neglected to reef my sail on the day that it got torn. Hopefully I'll get a few more years out of this sail, as I have a new sail cover this year. Good Luck!
Joe