Laptop use hinges on durability.
ThinkPads have a reputation of being the tough, durable laptops that are all business. Forget fancy or stylish, the ThinkPad lineage is all about being reliable and dependable.
Anyone who has had a loose hinge on his or her laptop can attest to the fact that it makes it very hard to use the computer. Lenovo demonstrated at the Venetian in Las Vegas how it tests the durability of its ThinkPad hinge. The hinge is designed to endure at least 30,000 opens and closures throughout its lifetime. Assuming that you own a laptop for five years, that's over 16 lifts of the laptop screen hinge per day.
It's a simple, piece of mechanical engineering, but a vital part to the computer.