How Do You Know When to Push Yourself?

I’m working on revisions of my NaNo novel, which will be pretty extensive, but right now my goal is 1500 words a day and it’s not been too taxing. I mean, I’ve been able to sit in front of the TV and watch movies and play a few games on Facebook and fool around on Pinterest and even make a few Pinterest projects. I figure I need a break after pushing myself through NaNoWriMo.

And then I signed up for the class Write 50 Books a Year with Delilah Devlin and Elle James. (Which, hey, was this week and I haven’t gotten any emails! Probably just as well.) I know I can be more productive than I have been this year, and I plan to be in 2013. I’d really wanted a novella out by Christmas, and it’s half-written, but that ain’t gonna happen. I really want to bundle my series, and I finally emailed my cover artist about it. I know the more I write, then sooner I can get the house paid off and then be a full-time writer, only I’m not sure I trust myself to make the most of that time, either.

How do you know when to push yourself, or when you need a break?