Is it okay to leave an External hard drive plugged into a desktop computer all the time?

Okay, now I know this may sound stupid to all the computer geeks out there but I just bought an external hard drive that pluggs into your comp, and I was wondering...if I planned on leaving it in all the time and rarely taking the cord of of the USB holder thing, would that be okay? Sorry, I know it must sound like a stupid question, but I don't know that much about the inner (or..outer?)-workings of computers...Lol. So please just save any criticism for once, to yourselves.