We didn't see any of the 3 of ours shed but as Michelle said, watch for the first B.M. oh and it is usually really small. 2 of ours took 3 days and 1 of them went on day 4.
If you miss it by a day or 2 it doesn't matter. Many of them don't eat so much even the first few days or more after they shed. Just keep them hydrated (I mist them till they shed and then put in a small water bowl)
It's usually a teeny green poo... he he. Sometimes so tiny they're easy to miss, especially if they poop in their hide. If I'm not sure, I put a couple mealworms in the bowl at about 5 days and they eat when they're ready.