Newborn babies should have their diaper checked at least every hour for poop or pee.
The diapers today can hold a good amount of wetness before needing changed so sometimes a baby even a newborn baby may need a diaper change every 1 or 2 hours during the day depending on how much they wet or poop.
A good rule of thumb is that newborn baby and babies under 1 year of age will usually go through 10 to 14 diapers per day.
As a baby gets to 1 year or older they'll use less diapers and at 1 year of age and above they should only need a diaper change every 2 to 3 hours.
Babies at 1 year old or older may only go through 4 to 6 diapers per day but as long as you change the babies diaper every 2 to 3 hours the baby should be fine.
When a baby poops you'll usually notice it and poop diapers should be changed as soon as you notice.
As the baby gets older they will tend to poop and pee on a set schedule so you can sometimes know about when they're ready to poop or pee and need a diaper change.