Do Space Marines Sleep?

Space Marines are allocated 4 hours in which to sleep. It should be noted that many chapters will not keep strictly by this agenda, and may shorten prayer times for example, or even cut out one of the activities in the list, such as free time, if the Chapter Masters do not approve of it.

Do space marines get tired?

Even Space Marine players I've talked to are getting a little worn out with the constant minor releases. Some have already gotten the supplement they wanted and are ready to move to the next thing. Other have spent months now waiting for their supplement.

Do space marines sleep in their armor?

Space Marines are trained to maintain a state of readiness so would remain in their armour at all times unless there was a point to removing it such as repair.