Is the Last Record Preservative system a worthwhile investment?

I clean stylus with Lyra stylus cleaner before each play. I think, the smallest bottle of the LAST was enough for 50 or 60 records but I didn’t count, so it’s $1 per record or less, almost like nothing even for me.

Been using both LAST and STYLAST, since they hit the market. Bought my first VPI RCM, about the same time (a 16 and now I own a 16.5) . Never have seen the first sign, of anything gathering on a stylus. Never experienced the first problem, regarding my records. The ones bought back in the, "Golden Years" of vinyl, still sound excellent. Some were played repeatedly, every business day, for years, to demonstrate my systems. Always clean(ed) and treat(ed) them, before the first play. Just another happy camper!

Yet another happy user since 1982 here.  I can't say that it improves the sound quality, but it does drop surface noise near to the limit of whatever the vinyl material can deliver.  That might seem like it improves the sound simply because the S/N ratio is maximized.

I have found LAST works quite well on all the vinyl I've purchased pressed from ~1955 to the present.  As others have noted, the key is starting with a clean, dry surface.  If the vinyl is new, I use the LAST Power Cleaner (mold release remover) first, then I use an ultrasonic cleaner with distilled water and a splash of LAST machine cleaner solution for everything, new or used.  Another wet clean with LAST cleaning solution and my trusty Discwasher brush, a thorough dry and then the surface is ready for preservative.  If you've gotten everything right, you can actually feel the preservative bonding with the vinyl while applying it; the brush seems to move with less friction. I'm sure that's due to the molecular effects visible in the micrographs referenced above.

FWIW, I've also used Stylast and the LAST stylus cleaner since they became available.  I've never identified any audible difference, but I can say I've never worn out a stylus.  The magnets have gone south first.

From my perspective, a good value proposition for a modest investment in happy listening.

I decided to use Lyra stylus cleaner instead of LAST because they claim it does not dissolve the glue, and it doesn't.
Besides, I have $500 MM cartridge and don't worry about stylus wear, it's $375 to replace. For now, after about 700 hours of play it is not far from new.