Can I sustain life without it? Yup. Last I checked, it doesn't assist me in breathing, eating, etc. Would my life be way less convenient without it? Absolutely.
Hey, the London School of Economics is conducting a research piece on the impact of push-mail technology on productivity and work-life balance. There's been so much talk (gripe? ) about the impact of BB's and so little data to show. It'll be interesting to see what comes out of it.
I could as long as I have another phone to use. I like my phone, bit I wouldn't die without it. I went for 3 months without a phone at all earlier this year.