It’s very important to always be prepared for whatever may happen with your child. There have been many times when a meltdown was prevented because I brought Mj’s favorite toy or snack along. I never left the house without:
A juice box
Crackers (usually gold fish)
MJ’s favorite “bouncy ball” or robot
MJ is almost 13 years old and I still always leave the house with at least a snack, earplugs, and his tablet. It has saved the day on occasion when we get stuck in traffic, have an unexpected delay, or a sudden change in plans.