I always wondered why most Smiths I have taken the plate off of are always so dry. New ones, old ones seems S&W does not believe in any lube to speak of.
I (who have every cleaning and lubing product know to man
) am now trying out the Mil Comm TW 2500 oil and grease. Seems like great stuff and not just for Sigs
(got a free sample with the guns). I just bought some of each. I think this stuff may last a bit longer than say Rem Oil, Breakfree CLP etc. I think Ballistol (Sportsmans oil) which is pretty much just mineral oil will last a long time. Eezox is a dry lube that also lasts a long time.
http://www.mil-comm.com/