Ideally you should get them out to play and interact with you in a large safe play area, for at least 1 to 2 hours a day
You need to interact with them every day, even if it is just for a few minutes …… this is essential because you need to know what is normal for each rat and you need to notice when they are not acting the way they usually act - so that when they are behaving differently, you will notice right away .... a behaviour change may mean that there is something wrong …. rats hide illness so by the time you notice something is wrong, you are well into a medical emergency
If they are in a huge cage with lots of interesting things to do and are able to get the exercise they need to be healthy and maintain a healthy weight, then you do your best at getting them out - strive for 1- 2 hrs/day but know that they are happy and healthy and have each other so just do your best about getting them out to play in a safe play area with you.
Since you are in the USA, you could get a large martins powder coated rat playpen (martinscages.com) where they can play, unsupervised, when you are too busy to interact with them. I have posted a couple of pics of my large martins powder coated playpen below (44 inches by 44 inches by 24 inches high) Since it has a flip top lid, they can not get out of it. and it folds for easy storage
** Note: A chew log appears in these pictures. The chew log has honey in it so some rats will think it is food and instead of just chewing it, they will eat it and may get an intestinal blockage and die ….. I have some of those logs in my pictures but I have since thrown them out because I decided that I did not want to take the risk.