When do I have to cancel the Netflix subscription?

30 day trial

Whenever you want. If you don't want to pay before the trial ends.

So that I don't have to pay

You can cancel at any time and receive an email when the subscription ends.

So that I don't have to pay

Within the 30 days

you can cancel it on the first day and have trzd. The 30 days

Before the trial period ends. It doesn't matter when exactly, the trial period runs until the 30th day.

You can cancel it whenever you want.

Then you just finish it during the trial period. You can end it a day or a week before the trial period ends. It doesn't matter. The trial subscription still runs for 30 days.