Re: leaving sails on the boat during winter...horrible idea?
Bah. Properly prepared, the main can survive on the boom during the winter. I've done it because I sail in sub-freezing weather if the sun and wind are right. I also went more than 4 days without visiting my boat.
However, if you're certain that you're not sailing during the winter, and you're going to leave the boat unattended for weeks at a time, just take the dang thing off and eliminate the risk.
I do agree that a roller furling jib will be ruined though. I use hank-on jibs, so mine are always stored in bags.
This winter, I have an option- I will probably put my new mainsail away, and bend on my ratty, 40 year old main for winter sailing if the long-range forecast looks promising.
S/V Old Shoes
1973 Pearson 30 #255