pfft. If your chain comes with a grease that's been thoroughly installed by the manufacturer, I see no reason to remove it. http://www.sheldonbrown.com/chains.html …and Sheldon Brown agrees. Efficiency is an irrelevant consideration in this instance. Lube the chain as best you can, clean it regularly (GT85, rag to wipe out the dirt, green lube then another rag to take off the excess), keep the crap out.
The Park Tool drop-in (stamped steel) chain checker is still one of the best and most reliable chain stretch tools I've come across. Simple, just drop it in and see the result.
http://parktool.com/products/detail.asp?cat=5&item=CC-3
Most manufacturers recommend replacing the chain at around 0.75% stretch – at this point you can usually replace the chain without having to replace the cassette, at least the first or just about second time. By the time you get to 1% stretch it's usually wise to replace the cassette at the same time because of chain "stretch" (see the Sheldon Brown article).
In other words, if you're careful about monitoring your chain wear and replacing your chain regularly, you can usually get through a couple of chains per cassette.
It's the sort of thing it's worth finding out about and keeping an eye on. Or finding out about and deciding that it's too much bother, and replacing your drivetrain altogether when it's all worn out.
HTH!
: P