We talk a lot about automating tasks to make things easier on yourself, but when you go overboard and do it too much you don't really get that much bang for your buck. XKCD's handy chart shows you exactly how much time you'll gain when you automate tasks.
The chart breaks it down pretty simply. On the top you have how many times you do a certain task each day, and on the left you have how much time you'll save. Of course, it's not perfect, and as Boing Boing points out a five year return on automating certain tasks is unlikely:
I think I'd halve the figures Randy gives in this chart, because many of the routine tasks you automate will change in some significant way in less than five years and require further work. Also, the chart fails to account for the losses in innovation and serendipity you suffer when you over-optimize a routine task so that you effectively can only do it in one highly constrained way.
Of course, automation isn't always just about saving time; it's also about making things easier on yourself, so it's often a cost-benefit question as well. Still, it's a handy chart to help make that decision before you dig into a big automation project.