generally smoking weed daily will make you "comfortably numb" (to quote pink floyd). I didn't even notice it for the longest time myself, but smoking too much will generally make you feel like being less active when you're high, burning out, or sometimes just the day after. it's all about moderation.

just today I realized I couldn't get myself motivated and stay on task with my studying. it wasn't so much that the weed made me "lazy", it's just that it made me comfortable in a lazy state and not notice. so I got up and just started doing a lot of stretches, then did some actual weightlifting and strength training, and then worked up to going out for a run. after a good hour of being active and keeping my blood pumping, I came right out of my stupor. so really all I can tell you is at least leave one day of the week weed-free, and don't let yourself forget about staying active, or else you'll get a little too comfortable doing nothing, whether that nothing be physical or mental.