Membership reoccuring payments, how does it work with Paypal?

How does Membership handle renewals? I'll use WPMU Dev as an example. If I've signed up for a 3 month subscription using paypal, will it automatically charge me again 3 months from now?

Is it using the Paypal PreApproval API to do this? It seems to:

Use PayPal for automatic payments to Incsub. Payments will be made with your default payment method unless you select a preferred payment method. To make changes, go to My money in your Profile, and update the My preapproved payments section.

If so, how long does this last for? Paypal says they have a 1 year and $2000 limit for pre-approvals.

Does Membership itself go out and do the transaction every 3 months or is it automatic?

Ultimately I want automatic subscriptions for as long as possible using the adaptive payments Chained payment stuff. That only seems to be possible with PreApproval and manually making initiating the transactions:

https://www.x.com/message/183762;jsessionid=05FF2731690CDDBBE651ECCD92D17425.node0#183762

I know this is a lot of questions, but this is the core of what our project needs to do so I really need to understand what is possible here. THANKS!