How much to include in a free tier?

If you're too generous, it doesn't pay the bills. But if you don't give enough, people won't bother trying it or coming back. What's the sweet spot for your product or industry? Trying to strike the balance for Gliglish, my 'ChatGPT for speaking languages' product (came out almost 20 hours ago! I should probably sleep!) I increased the free tier just now to see if people stick around longer.