To update just to update or to update because you actually have something planned out for your story?

So, I've been on and off the site lately because of the amount of work I have for my personal life; however, I always have my stories (my main one [urlhttp://www.mibba.com/Stories/Read/518334/Lifeline/]Lifeline[/url]) on the back of my mind. I wish I could update as often as I used to, but I'm pretty busy and top that up with lack of creativity to write a good update and it becomes harder.

I managed to write something pretty decent after a while and I've updated this story after a month or two of it being in hiatus; mainly because I really would feel like crap if I made a sucky update after months of the story being inactive. So, I've been with this question for quite a while now, do I update just to make an update even though the update will probably suck and it will make me hate the story?

Or do I update when I actually have something worthwhile and important for the story even if it takes me a month to do a simple chapter?

How do you deal with your updates? Do you think of yourself when wanting to make an update (sort of like "I'm a crappy writer for not making any update. And I plan on publishing! Surely the company would drop me immediately for lack of updates.")? Or do you think about your subscribers/readers/commenters (Damn, I owe them a good update for having stick with the story even though I haven't updated it in ages; this update better be great.)?