You know, I never ever calibrate my battery. I actually took the time to do it last week because it seemed like my battery was draining more than it should even though I was getting good ma readings during sleep time. It didn't do anything. IMHO, by the time your kernel settles, your battery stats will be properly "calibrated". Also, the cheap battery I bought does not appear to hold a charge as efficiently as my stock battery that is 20 months old. Oh well, the larger capacity still gives me better overall battery life than my stock battery.
And by "drain" I mean my stock battery will drop 1 or 2 percent overnight and my extended battery will drop about 5 or 6 percent. Not a wild problem, but there seems to be a noticeable difference.