2,000 miles. That's about how long it took for my chain to need lubricating again after I applied this stuff earlier in the summer. I should specify that all of those miles were done in "4 seasons in a day" Northern Ireland, a good percentage of them in overshoe-worthy rain over gritty, filthy, crumply chipseal farm roads.
In the past several years I have used a number of chain lubricants, pretty much the usual suspects you'll see in bike shops. Most of them have worked splendidly in good weather, and anywhere from decently to poorly in bad weather and gritty road conditions. What makes the NFS Chainlube stand out for me, is that it truly excels at the latter. Not only does it take longer to wear off in the rain, but it somehow attracts less grit and sand than the Other Brands I've used.
I should note that I am generally not big on bicycle chain maintenance. I don't go by any kind of schedule and only oil my chain when it starts making noise. In stretches of good weather, it can be a long time before a chain needs re-lubricating. The trouble is my penchant for cycling in bad weather. There have been times I've ridden in conditions where my chain has needed maintenance after a single sub-100K ride. That has not happened since I switched to the NFS Chainlube. This product goes on light, and fairly little of it is needed. This, in combination with how long it lasts, makes a $15 bottle go a long way.
NixFricShun Chainlube (NFS for short) is a product brought to you by the framebuilder-oriented cycling forum Velocipede Salon and it comes with a backstory. It's a fine story, but I won't focus on it here, because I feel it muddies the point. Point being, that this chainlube does not need a story, cause, or hip affiliation to help sell it. Though initially I bought this product to support Velocipede Salon, once I used it I became a convert. Then I bought a couple more bottles to give as gifts, and the cyclists I've given them to have become converts as well. Rain or shine, with an emphasis on the former, for me this stuff has gone the extra mile.