I have had several cats spayed and recovery times vary from just a few hours to a few days. You should inspect the wound regularly to make sure that she is not biting and trying to remove the stitches and keep her indoors for three or more days. One cat I had removed all her stitches the first evening. I took her back the next day and they were done again but she bit those out too so I just put disinfectant powder on them two or three times a day and the wound eventually healed up by itself but I don't recommend this! Six months later one of her kittens did exactly the same thing!
Good luck!