Scheduling free time

Hi! If I am not used to scheduling “free time” what would you recommend? Is it better to say, schedule 1 day a week or 2 mornings or half an hour twice a day or 15 minutes each hour? What’s a good amount of “free time” per week? I’m a stay at home mom and find almost all of my time is “blurred” – even when I’m not running errands etc I’m thinking about all the things I should be doing instead. I’d love any advice.