[karenchka]

I bought my new MacBook Pro 15” two weeks ago and it’s doing fine apart from the fact that the battery life is slowly diminishing. At the moment it’s reading 95% even though it’s plugged in all the time. Yesterday it was 96% and it was 97% the day before that. Do I need to be worried? What can I do about it?

[malone]

No need to worry. This is normal, and, in fact, desirable, behavior.

Batteries lose their charge naturally with time, and Apple notebooks do not charge it to full every time your battery loses a bit of charge in order to minimize the number of charge cycles to your battery (thus increasing its lifespan). Instead, only when the charge degrades down below 95% does it fill it up back to 100%.

[marsbt]

There is a lot of information about batteries in the documentation which comes installed on your MBP. But you can also read about the Li-Ion battery technology more at Apple - Batteries

But you should also keep an eye on the battery performance as it could have a manufacturing defect. Initial charge current is quite high for a Li-ion but it falls down to trickle charge (very low value) just before it fills up. So after that stage the battery is only given trickle charge so that it keeps the charge. Ideally it shouldn't loose charge when the AC power is connected to the laptop. If the charge keeps going down regularly, give it a complete power cycle and see if it makes a difference.