When going on vacation with a baby and taking diapers for your baby on the vacation you should figure out how many diapers your baby goes through in a day and in the week.
Then add at least 7 more diapers or so more just to make sure you have enough diapers and cannot get more right away.
For example a baby 1 year and under may go through as many as 8 to 10 diapers per day so you would need 56 to 70 diapers for the week.
But to be safe you might want to take 80 to 100 diapers.
It's better to have too many diapers than not enough diapers.
For a toddler of 2 years old and above they may only go through 5 to 6 diapers per day so that would be 35 to 42 diapers per week.