David from Bronx,ny writes
It is recommended to change Contrac bait out every 40-60 days if not eaten. Very cold or warm temperatures will mold or sour the bait faster. There are some instances when rodents can be resistant to a certain active ingredient in a bait and there may be instances where the rodents will avoid the bait all together (bait is old or spoiled, too many alternate food sources are available). We recommend changing to a bait with a different active ingredient every 4-6 months so that you will have fresh bait and you can avoid any issues with resistance.
Answer last updated on: 09/27/2013
