Scratched_back said:Most DMs worth their salt won't let a fighter sleep in full plate without magical assistance, it's just too restrictive. This way, when setting up camp and resting (i.e. without their armour) if there is any unexpected hassle, their AC isn't totally down the pan.
For what it's worth (and off topic, as we all know that the real world has no bearing on the rules...), I've slept in chainmail. And I've slept in plate armor. And I'm here to tell you the plate armor was a lot more comfortable. In plate, I wake up stiff (as a result of not being able to shift position while sleeping...you're basically stuck in one pose all night) and you get a bit cold because the air gap between the armor and your body leaves you a lot of space to warm with body heat compared to wrapping yourself in a blanket. In chain, I found it hard to get to sleep at all until I was totally exhausted...unlike plate, which is self-supporting, the chain weighs down your torso and abdomen (especially if you're on your back) and adds effort to each breath you take. Also, the weight of the chain tends to kill the circulation in the arms and legs.