I own a Sony Ericsson K750i which I had sent for repair 2 weeks ago since it was not being able to charge 
That was quite some experience living without my mobile phone for a period of time, and an opportunity to check whether it made any difference of having the mobile or not.
Firstly, since i got unlimited access to the internet and i use msn… i was most of the time communicating via msn or even skype. Incidentally all my friends have unlimited access to the internet so it was not a real problem to communicate with them when i was at home. I had no worry to put my mobile phone on charge. No calls in the middle of the night, no sms to reply… 
However It was quite a problem not having my mobile phone outside home… I depend a lot on my phone when am not at home. For example i do not use any watch since i get the time from my phone itself, and these two weeks i got quite some problems keeping track of the time. My mother communicates a lot with me through mobile when am away from home. But these two weeks she was not able to call me for anything. My mobile is also used to know where my friends are waiting for me… But without my mobile i had to search for them in that university campus… I was lucky enough as my search always ended in a short time… 
Well overall here’s a summary of the pros and cons of not having a mobile phone:
Pros:
- No need to spend money to recharge my account…
- No need to worry about charging my mobile phone.
- No need to reply to any sms…
(Joking… missed my friends… )
Cons:
- Lack of communication with friends when outside home.
- Really missed my friends when i was not at home…
- My own dependencies on the phone (e.g. Alarm clock and Calender, Time)
Well to conclude i should say i really missed my phone… It’s my favorite phone… 
Am so glad i got it back… With a new Casing… That was nice…
