How much should you feed a 3 month old bearded dragon a day?

Right now I have about a four month old beardy and I feed him 3 crickets in the morning (you can feed them whatever time but you want to try and keep that time consistant) , usually he/she (not sure which gender yet) will eat all three of them. So then if he does this I put more crickets in 1 at a time. When they loose interest in catching them that means there full. You want to take the extra crickets out because they can bite your beardy. Lastly before I leave in the morning most of the time I will leave him a salad. However I do not use romain lettuce it is composed mostly of water and does not have nutritional value. Hope this was helpful!
P.S If you need more help you can find care sheets online using google!