Does leaving my ne MacBook Pro plugged in to the power cord reduce battery life??

RunnerWRW wrote:

Does leaving my new MacBook Pro plugged into the power cord reduce battery life. i.e. is fully discharging the batter necessary.

No. It is the opposite it will prolong the working life of your battery by reducing the cycle count.

Determine battery cycle count for Mac notebooks

https://support.apple.com/en-us/HT201585

You can leave it plugged in as long as you like. Mine is pretty much always plugged in. Macs have battery management software onboard. I took mine off power a few days ago, plugged it back in, and not it's holding charge at 80 percent on my battery as it has learned my usage pattern.

<< i.e. is fully discharging the batter necessary. >>

fully discharging the battery reduces the useful lifetime if of your battery. That advice is Not appropriate for todays MacBook Pro batteries.