Find the times when you know you might have less success at that moment, can afford some failures, but will gain in the long-term. Certainly, you will on occasion pick days to practice that are not scheduled and will on occasion pick days off that are not scheduled. However, you should plan periods ahead of time that you give some lengthy breaks. Let the players know. They will anticipate this and will be able to work knowing that they have this time coming.
Parents can plan travel or family events.
You will know that this is time you have to get a break or prepare for the remainder of the season. Knowing your players major activities will help with this process. Plan ahead and make sure you don't need to be practicing at that time. Preparation and patience will make you a more successful coach. Whether looking at the areas of administration or skill development, being prepared and being patient for long-term success will bring success to your program and athletes.