Lep gecko

Question
My 1 year old gecko hasn't pooped for 4 days. I think we've been feeding him mealworms that are too large. I started soaking him in warm water,massaging belly and feeding a couple drops of olive oil today. He doesn't act too sick, just not eating as much as usual. How long can I keep doing what I'm doing before having to take him to a vet?

Answer
If the gecko is eating and drinking, he may be fine--sometimes they can go a few days without defecating.  If he stops eating, take him to a veterinarian.

Sick reptiles usually won't eat.  His appetite may be reduced from the stress of being massaged and oiled, lol.

Intestinal blockages or constipation cause nausea, which causes an animal to stop eating.  You can continue daily warm-water soaks until something is produced.

Obviously, switch to prey items that are no larger than the space between the gecko's eyes.  Feeding insects that are too large can cause serious problems.  Make sure crickets and mealworms are dusted with calcium and well gut-loaded, as these insects are too high in phosphorus.

A few other things to consider:
Internal parasites
Impaction (eating substrate, such as sand--it's recommended to keep leopard geckos on newspaper, paper towel, or tile, and not on particulate substrates like sand).
Blockage by chitin from too-large prey.

If you notice any signs of bloating, he stops eating, or this goes on for a couple more days, take him to a vet.