There is no fixed upper limit, so long as you are both comfortable. Just as there isn't an upper limit on how many hours a day you can spend cuddling and holding your baby, there's no real upper limit for how long you can spend carrying them. In your baby’s first months, they may be happily carried for a large proportion of the day, coming out for feeds and nappy changes.   As they get older and they become more alert and awake for longer periods, they're going to be more keen to get down, explore on the floor and play and come up to you when they're tired and ready for a snuggle.