I think writing everyday is a must if you want to be a writer, especially with novel writing. However (and this is my experience only so take it with a pinch of salt) I believe setting a goal can be counter-productive, for me anyway. If I sit at the computer, or with pen in hand thinking that I must write a minimum of 1000 words then you can bet your ass I'll get nowhere near that target, then I'll become stressed, unable to focus and feel like a failure (maybe not to those extremes but you get my meaning). If I sit down and think 'I'll write something, even it's only a few sentences, after all, something is better than nothing and every word counts' then I'm much more likely to write considerably more than a few sentences - sometimes not, but that's okay, the story is still further along than it was yesterday. The important thing is to keep yourself immersed in the story - a break, however short, can disrupt the flow and you spend more time re-reading to get yourself back into the mindset of the character than you do writing.
But again, this is only what works for me.
But again, this is only what works for me.