Nothing wrong with sacrificing one or two. I just did this with my first batch - put one in the fridge overnight after they'd been in bottles for about 12 days and tried it. The rest are going to condition for another week at least but it sure was good to know that my beer was going to be great!! IMO if you sacrifice one or two before you know they're done, you get a better feel for the conditioning progress. Plus you get to drink beer!