My Leo ate the next day. From what I hear anywhere up to two weeks is normal.
Just try to offer food if it doesn't take it don't worry try again the next day.
My leo hasn't ate in 5 days now, but when he's hungry he will eat.
I just offer food once a day and if he doesn't take I'll try the next day. I haven't tried to feed him in about 3 days now so I'm surprised he didn't eat today.
Take them out in 15 minutes if your Leo doesn't eat them. 15 minutes is plenty of time to tell if your Leo is hungry or not. Never leave crickets in a Leos cage overnight they will bite your Leo.
as said above it can take a few weeks for them to get used to their surroundings before they will eat, so dont worry. Just make sure that the temps are good at night time so that they have the energy to hunt, and no you shouldnt leave the crickets in, they can bite. also if they dont seem to do the trick try some mealworms
It SHOULDN'T. But it potentially could. I find that the younger they are, the earlier they usually eat. Usually doesn't take more than a couple weeks. I've seen adult geckos go for as long as a month though.