Had 12 months of riding MTB on a SRAM XO1 chain doing 30-50km a week and my chain is still OK according to my basic chain measuring tool.
I wipe my chain after every ride with a dry cloth and it has remained amazingly clean.
Really only reapplied after a wet/muddy ride as per instructions otherwise I have not had to put much on.
One drop per link on the inside of the chain, rotate for 12 or so times then wipe clean.
I'm no expert at all on lube but having previously used Squirt I have found this product to be really good.