I use rocknroll extreme too, but it gets very expensive and quite mucky if you apply as per the instructions.
These days, I’ve bought the 16oz bottle from CRC, prised out the squirty fitment and I dip the cleaned chain directly into the bottle, ensuring that as its dragged back out, it runs over the edge of the bottle top. This ‘wipes’ most of the excess lube back into the bottle and makes sure the chain is 100% lubed too.
It lasts the same as Candodavid says, since I ride with him. In the winter, all I do is put a sacrificial layer of finish line wet lube on each roller, which seems to protect the rocknroll lube quite nicely. If you do it in the dry though, it just turns into a stickymess.