[...] How Stuff Works, Battery University, and *gasp* Apple. I'd assume that Apple's situation is closest to the N9's since the battery in iOS devices isn't user replaceable, and it'd be in Apple's best interest to avoid making users get new batteries. Of course, I suppose it could be part of their devious plan to milk more money out of Apple lovers.
If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month
No, discharging and charging does not increase the life of a Lithium Ion technology battery.
When storing for more than 4 days these guidelines can better preserve the life of your battery: Do not store batteries for long periods plugged into or attached to any power source. This includes AC adapters and laptop security carts plugged into an outlet. Laptop batteries, including those stored in laptop systems, should maintain an Operational Storage Temperature of 0° to 35°C (32° to 95°F). Batteries may be stored in the laptop or outside of the laptop. Charge batteries before storing. The recommended charging time should not exceed 1 hour. Typically, this should charge the battery to between 80% and 100%. (Some discharge will take place over time. Stored batteries are expected to discharge 10-15% over a four month period, for your information.)