Question about screen time policies?

Kids are 6, 8, and 10. Currently doing 1 hour on school days, 2 on weekends. But during summer break we're all kinda losing it. The older two want to play Fortnite with their friends and I don't know how much is reasonable. My wife thinks we should be stricter. What are you guys doing? Are you screen-time hardliners or do you go more flexible?