I don't know how many times photographers repeat it to their students but I'm sure that you're already familiar with it: take your camera anywhere you go (when possible of course). I think it was the very first thing I learned when I was starting my adventure with photography few years ago and so far it's the easiest thing to remember. Probably because I really can't move anywhere without my camera anymore. My friend once said that a camera has glued onto my hand.
Why is it important to always have a camera with you? The answer is very simple and it's common sense: you never know when an opportunity for a great shot will be. It's important to have a camera not only in situations where and when you're expected to shoot but also in random situations, like a walk, family meetings, going out for a dinner, etc. Having a camera with you allows you to be ready to capture a moment that will pass and disappear. Scott Bourne goes a bit deeper into this topic in his article "Capture A Moment – Before It Goes Away Forever" on PhotoFocus.com.
1 November (Monday) was a public holiday in Belgium. I took an opportunity of having a long weekend and I went to Maastricht (the Netherlands) where I used to live before I moved to Brussels (Belgium) in 2009. I lived in Maastricht for about 5 years, so you can imagine I have lots of good memories from there. Going back to the city where I spent 5 years of my life was a great experience and even a time-machine, if you know what I mean. I took plenty of pictures during that weekend, counted in hundreds, and it's a great feeling to look at them now.