Picture the resources you have in a given day as being reset each morning. Every single thing you do, no matter how big or small, will reduce the day’s remaining resources.
Learn to queue up low-priority tasks that you can save for situations where you are short on time, energy, or other resources. In such states, it is very difficult to think clearly enough to enumerate such items on the spot. Potential entries can include errand calls where you know you will be placed on hold, catching up with old friends or slightly distant family members, performing outside chores, or catching up on the news. If you have more time but just as little energy, reading a book might be better use of your time.