Should I Reduce calories on a lazy day?

I disagree with pp that it doesn't matter. When I change my settings from "sedentary" to "lightly active" or back, it raises or lowers my calories accordingly, so your allotted calories are, in part, determined by your activity level. If you're less active than you have your settings set for, you could wind up overeating. I have Fitbit synced to MFP, and if I am "lazy" (i.e. less active than I have my activity level set to), it does take away calories in MFP...sometimes 200-300. That setting can be turned off, but I like it, because it motivates me to quit being lazy.