Should the signup flow ask for a credit card upfront?

Asking for a card at signup filters out the tourists instantly. Every person who gets through is serious, they convert at a much higher rate, and my trial-to-paid numbers look beautiful because the people who were never going to pay never even entered.

But it also costs me a huge number of signups I'll never see. Plenty of people want to poke around before committing, and the moment I ask for a card, they bounce — not because they wouldn't have paid, but because the ask came before the trust. I know because I do it myself. If a product asks for my card before I've seen anything, I close the tab and forget it existed.

No card means more signups, more feedback, more people who fall in love and then pay. It also means a flood of free users who never convert, a support load from people who will never spend a cent, and a trial that drags on for six months because nobody had to commit to anything.

I've seen companies swear by the card wall. I've seen companies grow entirely on frictionless signups. I've never seen anyone do both at once.

Which one did you pick, and did you ever switch — in either direction — and what actually changed when you did?