“If you do a trial, it's actually a much longer payback period — what finance people call float — than a lot of people expect. We have a 30-day trial which is a bit much for a mobile app, but we do it. 30 days, the user subscribes, Apple pays you a month later. You end up with up to a 90-day float.”

A 30-day trial is a 90-day cash float — Apple's payout delay starves you

Long trials look cheap on a paywall but starve cash flow. Greg's 30-day trial plus Apple's payout delay creates a ~90-day gap between ad spend and revenue — a critical input to whether paid acquisition is even viable while bootstrapped. Always compute the float before scaling spend.