Keep it in the fridge and it'll last forever and ever. Not really, but I used bacon grease for several months and it never changed smell or anything. I periodically topped off the top with fresh grease though, so maybe I just kept the rancid stuff out of reach on the bottom =P I threw it out because I wanted to use a different jar and was a little worried about how long I'd kept it. You'll be fine for a couple of weeks at least!
Just give it a whiff and keep it closed, it should keep the same smell for as long as it's good.