Plugging it in isn't just so it starts well. Most vehicles only have a coolant heater, but oil heaters are also common. Heating the coolant will help the oil warm up faster and reduce start up wear.
For me, sometimes I do, sometimes I don't. My truck takes forever to get warmed up, my car gets warm quickly. My parents always plug their rigs in.
If you're leaving the same time most days, get a timer and plug it in, it is better for it.