MacBook Air :: Shutdown / Sleep - Which Is Better For Good Lifespan?

I received my mba in the mail about two weeks ago, and since I have only shut it down twice. Once on a system update on the day I received it, and the other just five minutes ago. This last shutdown took a good 5 minutes, and I'm not exaggerating; 5 minutes, if not more. It took long enough for me to close the lid, went outside to smoke a cigarette, came back and the screen was still light blue with a "loading" animation toward the center bottom of the screen. I finally got tired of waiting and left it alone with it's lid closed and watched a program on hulu before checking it again. Then, it wouldn't turn on. I hit the power button and nothing. I held it down; nothing.

I had to hit the power button with my mba connected to the power source before it would turn on. The battery wasn't dead; it had over 90% left. But, when I did it again, the shutdown was instant...less than a second, and the boot up took less than 5 seconds. So, it got me thinking. My mba boots so fast, is it beneficial to always keep my mba on sleep? I can live with a 5 - 10 seconds wait before I get to use my computer. Does it hurt or decreases the lifespan if I shutdown and boot up on a daily basis? Which brings me back to the discussion I'd like to start on this thread....again for most of you. Shutdown or sleep? Which do you do, and why?