How much leeway do you allow yourself?

About 2 - 3 lbs (either side of target) or so but I'm pretty flexible. I'm usually right around 182/183 but 180ish on the low end and 185ish on the high end. It's not uncommon to have a "rough" weekend and be around 185 on a monday morning and drop to 180 by Wednesday (long ride Mondays and Lifting on Tues) before leveling back out around 182/183 by Thursday...rinse and repeat.