Not all burglars will knock on doors or ring doorbells but some burglars will come up and knock on the door or ring the doorbell during a certain time so they can find out whether you're there or not.
Then the burglar may even come back later when you're gone and break into the house.
Having one of those Ring Doorbells can help deter burglars because if the burglar rings your doorbell you'll be alerted to the doorbell and can see and talk to the burglar which will keep them away from your home.
Burglars don't always do burglaries at night because most people are at home during those hours and actually most burglars will break into homes during broad daylight.
But they'll do their best to hideout and not be seen and sometimes burglars will disguise themselves as workmen etc to go undetected.