It is not too bad to leave your laptop plugged in all the time. Due to recent technological advancements, it is no more true that having your laptop plugged in all the time can hurt your battery. When your laptop is plugged in, it uses the power from the external source with the battery being bypassed. However, the main hazard you could have in this case is the excess heat that may be produced due to the usage of an external battery source.
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