Never auto-renew by default.

Any time I sign up for something, I only sign up for a month and I immediately turn off auto-renew. If I miss it at the end of the month, I can sign up again, but usually I won't. If I get through another month, I'll consider a year if its a much better deal, but usually I won't.

The moment I see dark patterns in a subscription model (e.g., I lose my data if my subscription lapses, I have to phone in to cancel), I cancel and don't look back, even if I like the service otherwise.