Doesn't it sometimes seem like the longer you work, the less efficient you are? Turns out, it's not just all in our minds. I found this neat little fact on Quora, the Q and A site, which says working in blocks of 60 to 90 minutes is a great way to get more things done in a shorter period of time.
There's a famous study by researcher Anders Ericsson in 1993, which found that the master violinists all practice the same amount of time as the average players, but just in a different way. The best players will practice very hard for up to 90 minutes, and then take a break. The average player that keeps on practicing without taking breaks will do so with less focus, says Quora user Colin Gerber.