When to lower crib setting?

jlslaugh

I think DS's crib is on the highest setting but I'm going to double check when I get home. Either way I'm just wondering when to lower it. I saw in the FFFC that this is obviously a big deal. I don't want to sound like an idiot but DS can stand in his crib and the side of the crib comes up to his chest. I don't really see how he could get out but please let me know if I'm mistaken. Thanks.