Some of you people need to get a grip on reality. It's a chemical energy storage device. It's capacity and performance going to fluctuate with environmental conditions (temperature, humidity, etc.) as well as usage patterns.
Do you measure the fuel consumption of your cars this closely? "I got 32.7 MPG on my first tank of gas but only 32.1 MPG on the second tank. Is my car a lemon??? Should I take it back??//????/?"
If your hard drive's capacity dropped from 80 gigs to 78 gigs, then you'd have a problem. If your RAM went from 1024 megs to 1000 megs, you'd have a problem. The capacity of those items does not fluctuate based on outside forces. Also, unlike a battery, their performance doesn't degrade over time. Eventually, they'll stop working but that's what will happen. They'll stop working. It's not like your hard drive will turn into the tired old dog that doesn't have the energy to chase cats any more. One day it'll be working as well as the day you bought it. The next day it won't work. The battery, OTOH, will degrade and it will become that tired old dog that can't last long enough to boot the machine.
If you drew a graph of the performance, the hard drive and memory would be a straight line until the day they stop working. At which point, performance would drop from 100% to 0. A battery will show a steady, continual curve towards zero. Probably 10-20% per year depending on environmental conditions and usage patterns.
If you have to pay attention to know if your battery is losing capacity faster than normal, it's not. If there's something wrong with your battery, you won't have to go online and ask, "Is this normal?"
