On the one at the Best Buy store, in "laptop mode", if I'd tilt the screen back about 10-20 degrees from vertical, it would slowly fall backward until it the laptop was flat. It couldn't "stay up" when tilted back.
Sure, my Best Buy model probably received 1-2 years worth of wear/abuse in the 6 months since the machine came out, but that's still worrisome.
That's what I mean by wear and tear. Since the hinge pivots twice, it doesn't seem like they were able to design in enough resistance to hold the screen up as the hinge loses strength over time.
This laptop is rated for 25000 cycles. Based on For durability, we put the Yoga hinge through a cycle of 25,000 high-pressure open/close movements. The average maximum number a user would open their Yoga in daily use is about 15 times per day.
Let's do some math.
Best Buy is open 12 hours a day (9am to 9pm)
Suppose your Best Buy gets 4 customers an hour that play with this laptop
Each customer flips the screen 5 times
That comes out to: 4 customers x 5 times per customer x 12 hours = 240 cycles
After 6 months, that hinge has seen: 240 cycles x 30 days x 6 months = 43000 cycles
I think it gets a bigger beating at BestBuy (than designed for). And might get dropped too.