Your expectations on phone durability?

What is your personal opinion on how durable a phone should be?

I always put a case on my phone, so it's never been an issue for me. I just assume that my phone won't survive anything, whether it's a 5-inch fall onto carpet or a 5-foot fall onto pavement.

Then there are other hazards, like liquids, dirt, and sand. I don't expect my phone to survive those, either. Of course, my phone looks like a brick when it's inside a case, but that's the trade-off that I accept.

Still, are there conditions where you expect a phone to survive with no damage at all if it's not inside a case? Would you consider it a manufacturing defect if your phone still broke under those conditions? What conditions are reasonable, in your opinion?