Typically, it’s not recommended you travel with a newborn and you should wait until their immune system is strong before you embark on a holiday, but you should consult with your doctor about making this decision.
Primary age is that sweet spot in life when your child still has a childlike curiosity, enjoys cuddles, but also wants to gain a bit more independence. You will find less tantrums compared to toddler age, but you may find they get bored easily.
Older kids know what they are doing at this point, and you don’t have to worry about them getting into unsafe situations since they will have some self awareness and can take care of themselves.
Teenagers are arguably the perfect age to travel with, since they can appreciate the life lessons that travel gives and have an interest in culture, history and art.
The toddler age, in my opinion, is the worst age to travel with kids. I felt stressed, overburdened, and highly anxious. We should be travelling to experience lightness and joy, not heaviness and stress.