Actually, I think that things which get thrown into bags on a regular basis face more stresses than a phone in your pocket.
It could be jostling around with corners of large books, laptops, cables, random containers, etc. It can also have more space to accelerate when you swing your bag around, whereas a phone is held firmly your leg when you run/jump/etc.
Durability in a bag is what separates great electronics manufacturers from decent ones. If I buy something and it doesn't survive bag life for several months, which is quite common, then I write off the manufacturer as a creator of fragile throw-away devices. But I've never had a phone have any sort of problem from pocket stresses.
It could be jostling around with corners of large books, laptops, cables, random containers, etc. It can also have more space to accelerate when you swing your bag around, whereas a phone is held firmly your leg when you run/jump/etc.
Durability in a bag is what separates great electronics manufacturers from decent ones. If I buy something and it doesn't survive bag life for several months, which is quite common, then I write off the manufacturer as a creator of fragile throw-away devices. But I've never had a phone have any sort of problem from pocket stresses.