14 days, no questions asked.
But yeah, smart watches are pretty pointless. Unless you're a businessman who needs to look at his phone every 5 minutes for urgent updates, it's a pretty needless luxury item.
There's no reason to turn your iPad off and doing what you suggested won't have any effect on battery life.
To make the battery last longer, keep the iPad charged to less than 80% at all times.
A lot of cordless drills still use Nickel Cadmium batteries because weight isn't such an issue. And uninterruptible power supplies and backup generators use lead-acid batteries because it doesn't matter how much they weigh.
The only advantage of Lithium-Ion batteries is that they're lightweight so you can put them in phones and computers. They have the disadvantages that they're expensive, not very durable, don't have many use cycles, aren't heat resistant, and so on.
You mean interest in a product rises immediately after it's announced and falls once it's released? SAY IT AIN'T SO!
This means that companies should stop making advertisements because people will be less interested in a product once the ad goes away.