A subscription is where ReadingHabit is heading, but the launch deal is renewal-free: one payment instead of about $8 a month for as long as you keep reading. At that rate, the one-time price pays for itself in about 15 months (and you have far more reading than that left in you).
Nothing renews and nothing expires. Once the subscription launches, this one-time price goes away. If you've already bought it, nothing about your account changes.