Saw a comparison chart that shows 1.1oz Silpoly as having a Hydrostatic Head of >1500 when "new" and >492 when "aged" but it does not define what "aged" is. I've done a couple of DIY tarps with the 1.1oz Silpoly and they get used on 5-6 trips per year. Does anybody know how long the Sil/PU coating typically lasts on this fabric?

Thanks.