How durable is the iPhone? I plan on purchasing my first iPhone soon, but I am really worried if this phone would last, I usually keep my cell phones 2-3 yrs. Would it be best if I buy a case for it when I am out, but take it out of the case when I get home so I can use the dock? I usually baby all of my electronics, such as my iPod, but even then, accidents happen where the iPod accidentally slipped out of my hand, and the top chipped. The last thing I want is a broken iPaperWeight. The glass screen worries me just a bit. Thanks in advance!