I just…apply common sense. I’m curious as to how many DMs would allow characters to sleep in armour, for example, in any edition. Being attacked in the night and having to fight unarmored is a fun challenge; it happened just a couple sessions ago.
The issue I generally have with the "no sleeping in armor" is that
- I've never slept in armor. I have slept just fine on rocky ground with no or minimal padding. I slept fine. If we needed a bed and PJs to sleep, humanity would never have survived.
- Armor is generally unrealistic in D&D, why make sleeping an exception? Well made plate armor should be virtually impenetrable to most normal weapons, even early firearms. Yet we don't blink an eye that "leather armor" (if there really even was such a thing widely used) let's people get basically as much protection as plate.
- It only affects heavy armor. Like somehow brigandine (studded leather in D&D) would somehow be completely okay.
- The monk, wizard and barbarian don't care, the rogue is barely affected, the PC that decided to use the generally suboptimal choice of being strength based is SOL.
- It's not a "challenge" if 5 out of 6 PCs in the party are basically unaffected, it's a "Gee too bad you didn't choose to build a dex based character."
