HOSTILE TAKE-OVER ATTEMPT - BEWARE "NG 10 Years" competition: RESULTS !!!https://nikongear.net/revival/index.php?topic=11252.0Current status: 89/150 supporters
Just a note on the 24/2.8 AI. I have one of those, bought in bargain grade from KEH over a decade ago. It is still smooth as butter. This is a CRC lens, I think, which means it's a bit more complicated than a single helicoid, so I'd definitely have it fixed or fix it if it doesn't free right up with use.
You were lucky to get one that didn't need re-greasing. Of the roughly 12 used Nikon manual focus lenses I've bought from KEH over the last decade or so, only 1 didn't need re-greasing.
I've had much better luck. Most of my manual lens purchases from them go back more than a decade. I guess I beat you to the good ones.
A decade ago the grease was 10 years younger and still good.
I bought a 105 ais. micro NIKkOR on eBay and the focus was really stiff.
But now it is 10 years older and still good.