My daughter is 2 1/2 years old. Before we had ever given the shot we were much more reluctant to give it. The first time she needed it we waited to see if oral meds would work. Well her tummy had been upset (but no vomiting) so I guess the oral meds weren’t getting absorbed. She had a high fever that would go down and spike back up, all night long. We thought we were out of the woods at about 3am. I set the alarm and checked her at 5am and it spiked up even higher and I got very scared. This is when we gave her the shot and she responded sooooo well that I wished we had given it at first instead of all that juggling all night long. We called her ped an he said she didn’t need to come in uless she took a downward turn. Now, when we think she needs it we give it much sooner. She responds so much faster than not giving it. We’ve given it for vomiting, high fevers (she had a 103.6 F this summer!! We didn’t know it as we were traveling and she said nothing. THen she vomited obviously beginning of a crisis. ) and a hard head bonk where in 1/2 hour she vomited and was lethargic. I agree that you will know when to give it. Just trust those informed instincts and know it’s the best for your child. Julia