I think if you live in an area that has an OD fleet, and you don’t need to race in phrf or orc, Dacron is just fine. I felt you could nurse 4 seasons out of a Dacron main. That about $600 a season especially if it was a radial design that allowed for a bit more tweaking and adjustment. Not a bad ROI. At that price point, I rather buy a new Dacron sail, then say my 4 year old 3di is “looks pretty good”.
Although I love my 3di Genoa, they are nearly double the price of what was 3dl or a paneled radial Genoa. I still question why the class allowed 3di genoas to be honest, instead of requiring a paneled laminate tri-radial sail with a minimum bag weight hat would allow for extra taffeta on the back 1/3 overlapping portion of the sail