Re: stiffen sails - how often?
Yes, the sailcare offering seems to have mixed reviews. Some say it makes them like new, others have issues with shrinkage. I think as to how often, I don't think you would want to do it more than once. Seems to be a last ditch effort to try to save an old sail, not really part of routine maintenance as far as I can tell. I am sure Sailcare will say different, but that is to be expected. I think for someone who races once a week you would want to consider new sails not "stiffening" and I would consider once a week pretty often. Now if you raced a few times a summer that is different.