Well, this is a tough one. I would say that computer is a need and good way to kill some time if you don't have anything planned.
If I have all-day plans then I don't need computer. I usually use it every day, I turn it on when I wake up and leave it on all the time I'm in the house.
I check email first then do other tasks if I have them. I usually make arrangements with my friend and colleagues virtually (I rarely use my phone, I have all apps installed on my laptop) and if I need to check something with them, computer must be on.
On the days I have everything arranged in advance I don't turn it on, there is no need and I know I will be late for meeting if I start browsing
When I go on vacation, I don't even think about computer nor I take it with me. Vacation is reserved only for personal interaction and I'm really glad I do this.
I've seen some people, when on seaside, instead of taking sunbaths and swimming they prefer sitting in an internet cafe and playing games - that can't be a need, this is addiction.
This doesn't make much sense to me - you could've stayed home and save money you paid for vacation.
We do live in a modern world, but it is a good thing to spend time in old fashioned way it - it makes us much closer