Welcome to the Dell Community @niv yefet 

Yes it is safe to have it plugged in all the time.

Your laptop has a "SMART" power and charging system.

Your battery, laptop and AC adapter all communicate with each other to charge the battery.

So when the battery is full or at the % you designate it will stop charging.

Most recommend setting the custom charge to 80% ~ 20% using Power Manager.

Best regards,

U2

There is nothing wrong with plugging in the laptop all the time.

The battery will not be damaged if you work while the laptop is plugged into a power source.

Ensure that you completely charge the battery and completely drain it at least once a month.

@RuskinF  The advice to fully discharge the battery at least once per month is very outdated. That was useful for NiCd batteries that had “memory”, and filly discharging them once per month avoided that. But laptops for a long time now have used Li-ion chemistry, which does not have a memory issue, and fully discharging them is actually detrimental to their longevity, so in addition to being outdated that advice is actually counterproductive.  

@niv yefet  It’s fine to leave your charger connected all the time, but there are some things you can do in order to preserve the longevity of your battery if you will be doing that. See my reply in this thread: https://www.dell.com/community/Inspiron/If-the-charger-is-plugged-in-at-100-battery-life-will-it-harm-my/td-p/7278297