A 2 year old uses on average of 3 to 5 diapers per day.
Although some 2 year olds may use 6 to 7 diapers per day depending on how much they drink and how much they wet.
My kids when they were 2 years old would use 3 and sometimes 4 diapers per day and as they got older sometimes they would only use 2 to 3 diapers per day.
As long as your 2 year old is having at least a few wet diapers per day then they are hydrated and healthy.
Diaper changes are usually needed every few hours and sometimes only ever 3 to 4 hours.
The more the toddler drinks the more they will need to wet and if they poop then they should be changed after about 10 minutes of noticing it.
However if the 2 year old is sleeping and they poop and it's not bothering them or waking them up then it's safe to leave the 2 year old in the poop diaper overnight.