Practicing and intent are what makes us lucid. Even if we stop practicing, the intent still will be there, but we are more in the "i'm not gonna worry about getting lucid right now" attitude. And that often helps.

Lucids can not be forced. We can prepare ourselves and then just KNOW that we are going to be lucid, instead of strong WISH to be lucid. As Rothgar mentioned, that's why many report getting a lucid right when they decide to take a break from praciticing. Because we stop forcing it and feeling bad if we don't get lucid.