If the screen limit in your house is only your preference, every evening turns into a negotiation about your preference. Borrowing a published figure, roughly two hours a day of leisure screen time for a child over two, moves the argument off you.

What the research says

A literature review of children and adolescents links heavy screen use to poor sleep and to cardiovascular risk factors, and reports that duration, content, after-dark use and the number of devices all matter, not just the total. A narrative review of sleep in young adults points the same way, finding stronger associations for bedtime device use and addiction-like patterns than for total screen time. Both review observational work, so they support shaping the hours rather than proving that any particular ceiling is the right one.

Strength of evidence: one line of research. A single study, or a theoretical account.