Lore Question: Space Marine Suits, and the off-duty time of those under the Imperium?

I don't play the games, but I've been getting more and more lore on my feed, piecing together the grimdark fabric of this universe, and I've got a question. In Starcraft, their "space marine" armor is described as a prison that's very much bolted on to someone. I don't think Master Chief's armor is supposed to come off either? Doom guy?

I've seen some cinematics with space marines taking off their helmets, which seems pretty common, and they aren't exactly bloodthirsty machines, seemingly having a concept of mercy and humanity outside of their wild devotion and insane murdering skills. So my question has two parts.

1. Does the armor come off, is it meant too, and how often does it happen and
2. what does space marine down time look like? Prayer? mediation, training? pjs in the mess hall?