I also saw the stefan sagmeisters's Ted talk and yes it was very refreshing and inspiring...but he of course can afford a sabbatical of a year. I can't dream about doing such a thing since bills need to be paid and my boy needs food
Nonetheless it's good advice to take a step back and come back with new ideas/perspectives.
I try to sketch everyday...but I don't
It sure is necessarily because it is a skill that is hard to master but easily 'unlearned' as some of you have mentioned.
Sketching is uber-important for idea-exploration and development. If you are bad/slow at sketching you will not spit out as many ideas/variations as a fellow designer who does know how to sketch. Anyone who can't sketch seeks refuge in CAD-environments. Be it illustrator or some other computer-aided-design-software. Sure you can do some nifty shit with those packages but it'll take time and effort. And that is a luckury you normally don't have (time). If you are good and fast sketcher you can explore many ideas in a short time. I sometimes explain it to my students with the following analogy: "imagine you and me dueling with pistols. you have the old-skool pistol. Just one bullet. But I on the other hand have a super-mega-automatic-2000round/minute-machine-gun. It doesn't matter if I miss 90% of the time. I will shoot you about 200 times. So it's really a question of quantity will deliver quality.
Summarizing: "If you don't know how to sketch you'll put way to much time in visualising just one idea while someone who does know how to sketch will have explored about 50ideas in the amount of time you have spent visualizing just one."
So yes...you can never sketch enough....