I believe that a Natural 20 should always be celebrated. Crit Ability Checks don't "exist", per say, but I allow them to help somewhat.

— Matthew Mercer (@matthewmercer) October 29, 2016

@Zardozindustry @mattcolville I try to keep the Nat 20s a little more restrained so players aren’t just rolling for Crits on everything. Rolling for crits on everything has the same chance of rolling for crit fails, though… 😉

— Matthew Mercer (@matthewmercer) October 29, 2016

@CptSupremeThere are some “one a million” shots that a single nat20 shouldn’t be enough for, but that’s what skill challenges are for. Aye. Grog rolling a Nat 20 on an Int Check doesn't mean he suddenly knows the needed info, but he may recall an obscure clue

— Matthew Mercer (@matthewmercer) October 29, 2016

@HaydenTownleybut do you belive in “crit fails on ablity checks”. Such as stealth. I do, but not to a disastrous degree. Crits both ways make for great narrative spins!

— Matthew Mercer (@matthewmercer) October 29, 2016