A laptop that's always plugged in is sort of like a kite that's always nailed to a wall -- it kind of defeats the purpose of its manufacture. Aside from that, though, while there are some reasons why an always plugged-in laptop is an advantage, there seem to be more factors indicating that leaving it plugged in at all times is not a great idea -- whether you're at the office or working from home.
If you're concerned about a higher energy bill due to leaving your laptop constantly plugged in, don't worry that much. For one thing, laptops are more energy-efficient than desktop computers. Also, an article on the website Slate notes how leaving a laptop plugged in generally uses less electricity than when you charge it fully, unplug it and then recharge, since there's energy lost in the charging process. Even if battery chargers become so efficient that no energy is wasted while charging, operating the laptop on AC current is typically more efficient than running it off of the battery's DC current.
Video of the Day
If watching your carbon footprint is a prioritized concern for you and your business, then leaving your laptop plugged in is a good way to go -- while you're actually using it, that is. When you shut down your laptop for the day, you should unplug your laptop cord from the wall outlet. Otherwise, the cord's power adapter and charger will continue to draw small amounts of current, and over time that will contribute not only to a slightly higher electric bill but also to increased carbon emissions.
There's also the matter of how leaving your laptop plugged in affects the computer itself, particularly the battery. Points of view differ regarding how laptop batteries are affected. For example, the aforementioned Slate article suggests that, in general, laptop batteries aren't that affected by a laptop staying plugged into the wall. However, other sources, including Apple and Microsoft, say that you should unplug your laptop in order to "exercise" the battery. Allowing the battery to exhaust itself and then be recharged at least once a month or even a few times a week will lengthen its lifespan, these sources say. However, check with your laptop's manufacturer for recommendations particular to your laptop.
To further length the life of your laptop's battery, don't leave it exhausted and in an uncharged state for long, since extended periods without being charged can weaken the battery's chemical mixture. Furthermore, avoid keeping your laptop in extreme temperatures, which will also wear on your battery's life. Also, when unplugging your laptop, don't pull from the cord line but from the cord end, nearest the laptop. This will prevent damage to the contact point inside the laptop's cord socket, which helps keep the cord in place and connected.