Question about Lightning Network and off chain scaling

I am trying to understand LN and the effects on scaling. Take a typical example: I want to buy some coffee.

If LN is used, two transactions are created, but not broadcasted. If I buy something more, the transactions are updated, but still not broadcasted.

When will this transactions be closed in practice? Is it a matter of minutes, hours or days?

If they are closed before the next day when I want to buy coffee again, it doesn't help scaling much, will it? Or is it something I am missing?