Same here! I used to keep it plugged in all the time while using my old Samsung laptop [it has a battery charge limit to only 80%]. Now I just bought my new Dell 5593 and I prefer to do the same [leaving the charger plugged] all the time instead of charging the battery multiple times a day.
I work from home and I noticed when using the laptop based on battery the fans keep working and feeling an overheating while working.
Today, I decided to keep the charger plugged even after the battery charged 100%... I see no overheating, no fans running, great performance, and a stable work environment.
Hope this can help someone.