There is nothing my PDA can do which I could not do some other way. I could keep my diary and address book on paper. I could manage my finances in the desktop. I could buy a newspaper. I could play patience with a pack of cards. I could listen to music or audiobooks on an iPod. etc. etc.

However, with a PDA, and even more so when it has an internet connection, I can do all these things with one small, easily pocketable object. I like to travel light, but I also like to be prepared for anything. E.g. if I go somewhere and decide to take a music player to keep me entertained, I also get to take along my diary, to-do list, password database, weather forecast, TV guide and all the rest, without any extra effort. It is all there in my pocket should need to know whether it will rain on Thursday, or whether I am free on June 22nd, or what the PIN number for a little used credit card is, or the password for a website I have only visited once, or ... The list is endless. And that is why I have to have a PDA.