While I can't call laptops durable (see Websters) your 7 hour request is iffy.

http://www.notebookcheck.net/Lenovo-Yoga-3-14-Convertible-Review.138000.0.html hit 7 hours but that's a new battery. After a year, the battery will wear down and unlikely to get 7 hours. Also under load it plummets to 2 hours 15 minutes.

So to hit 7 hours as it ages you need to start at a 14 hour battery. Battery time is expensive in cost, weight and more. I'd be sure to have it on AC anyway.