How many buy-ins
Cash guidelines vary, but beginners should think in dozens of buy-ins for the stake they play — not two. Tournaments need more because variance is higher.
Example: if a buy-in is $200, a fragile 5-buy-in 'roll' means a normal downswing forces a shot or a panic move-down. That's not toughness; that's undercapitalization.
Write your number. Obey it when you're winning too — shot-taking without a plan is how rolls vanish after heaters.
Write your buy-in count rule. Obey it after heaters too — shot-taking without rules gives it back.