Apparently, debates are ranging around the issue of whether curing is really needed beyond the date that the soap stops losing water weight. One of the claims is that there is no "proof" that the longer cure does anything for the soap.
Well, my experience may be subjective, and I may not be able to provide a scientific answer that supports my experience, but my soaps become infinitely better with a longer cure. Perhaps that is recipe-dependent, as I am generally a low-to-no OO or PO soaper. My recipes are also fairly low CO except for my salt bars. So I'm soaping with a lot of lard and tallow, with smaller amounts of butters, CO, AO, and castor.
IMO, the long-cure rule is especially true for my salt bars, which change tremendously over time. The lather becomes softer, denser, and less stripping. After using a lightly-aged salt bar, my skin is dry. After using a fully-aged salt bar, my skin feels very clean, with no residue - but not dry at all. My blind testers (family and friends) confirm that the longer-cured bars are less stripping and have a nicer lather feel, too.
My high-lard bars also change a lot over the cure, but in a different way. They don't lather as well for the first four months. Somewhere between 6-8 months, the lather improves greatly, not so much in amount, but in the creamy feel. At 10 months, they feel so nice that I keep lathering and washing my hands long after they are clean.
