Armor, Weapons, and the Rules People Forget Exist
Most players pick their armor once at character creation and never think about it again. That’s a mistake, and not because of the AC numbers.
The Armor You’re Actually Wearing
Armor comes in three tiers: light, medium, and heavy. Light armor adds your full DEX modifier to a base AC of 11 or 12, which means a rogue with +5 DEX is walking around at 16 or 17 AC while still having no disadvantage on Stealth. That’s the sweet spot for DEX-based classes, and it’s why rogues tend not to feel squishy even without much gear.
Medium armor caps your DEX bonus at +2, topping out at 15 AC with half plate. The real gem here is breastplate: 14 base AC, no Stealth disadvantage, and you only give up one point compared to half plate. It’s the quietly correct choice for any medium armor wearer who wants to stay useful outside of a fight.
Heavy armor is a flat number, DEX irrelevant. Plate sits at 18, and with a shield that becomes 20. You will have disadvantage on Stealth in all of it, full stop. The trade is simple and honest.
The rule that actually matters, though, is don and doff times. Light armor takes one minute to put on. Medium takes five. Heavy takes ten. This is a rule that gets quietly ignored at a lot of tables, and it causes genuine problems. If a player is stripping off their heavy armor mid-dungeon to avoid the Stealth penalty and then asking to put it back on before a fight, the answer is that they are standing in a corridor in their undershirt for ten real-world minutes. Send in a guard.
Weapon Properties Worth Knowing
The Loading property is the one that surprises people most. Weapons with Loading, including heavy crossbows, can only fire once per turn regardless of how many attacks you have from Extra Attack. That longbow looks like an upgrade over a shortbow until you realize it also has Loading, and suddenly your Fighter is firing once per turn instead of twice. Always read the properties, not just the damage die.
Finesse lets you use DEX instead of STR for attack and damage rolls, but you can choose which one on any given attack. That flexibility is genuinely useful on a character who might be reasonable in both stats. The tradeoff is that finesse weapons tend to cap out at d8; there are no d12 finesse weapons. That distinction belongs to the greataxe and the lance, both STR weapons.
Two-weapon fighting requires both weapons to have the Light property, and the bonus action attack does not add your ability modifier to damage unless a feature specifically says it does. Versatile weapons let you scale between a one-handed and two-handed damage die, which is a quiet way to give yourself options without committing to a shield or a two-hander.
Improvised weapons default to 1d4, but the better ruling is to find the closest actual weapon in the table and use that. A chair leg is a club. A bar is a greatclub. Reward the creativity, use the existing math.
Silvered weapons are worth mentioning to players early. They bypass resistance to non-magical bludgeoning, piercing, and slashing damage, which means they fill the gap between “mundane weapon” and “actual magic item” without handing out power. Building a small quest around acquiring one is good design: the reward is tangible, meaningful, and bounded.
For reference: Player’s Handbook Chapter 5, pg. 144-149 (armor and weapons), and Xanathar’s Guide to Everything pg. 78 (sleeping in armor).