i wouldn’t spend that much time, but i would focus on what you want to get done. to me it’s better if you do things you need/want to do and eveything else later when your more comfortable with your routine/plan. TL/DR: don’t spend to much time and try to spend under 10 mins a day.
It really depends on how much time you have during your day. What’s really important is when you plan your days. A while ago, I used to plan my days right before bed so that when I wake up I have an entire plan to follow, but soon I started waking up and feeling lazy on some days and I can’t get everything done which causes me to become even more lazy and sleep through my day. I tried planning my day in the morning after that and let me tell you that was the best decision I’ve ever made. Because on some mornings you’re not that productive. On those mornings, you’re gonna have to follow the plans you made when you were productive. So now, I wake up and make a plan based on my energy that morning and make it through my day with a productive mindset.
I usually spend about 5 minutes planning my day. You shouldn't spend time planning reoccurring activities (habits) like exercise, as they should already be added to your day automatically at a specific time. Your habits should be apart of a morning routine that you follow every day and only need to plan once, which is when you create the routine. Once you realize that you don't need to plan habits, the amount of things you actually need to plan is very small and specific to just that day.
I like to plan my day as a quick 5-minute meditation. As I close my eyes, I try to visualize my day playing out the exact way I want it. As you visualize, you're forced to confront what your goals are, why you want to achieve them, and the consequences of doing them. And afterwards, you REALLY want to do them, because you just visualized how good it would be to follow through. You're basically imagining the best version of yourself, and if you keep doing this every day, you will gradually become closer and closer to that version of yourself.
I barely plan my days because I don't go out much to friends homes and hang out with them. But if I did, I would say like maybe 10 – 15 min so it doesn't become a waste of my day.
as much time as you see fit to set all of your goals in an achievable manner. this could be anywhere from a few minutes to a few hours depending on how much planning you deem necessary, but either way i find it a calming experience to just relax and focus on how i want to improve in the future