I know not what this spontaneity is that you speak of. I have very few gaps in my schedule, and that's usually extended out for the next two weeks ahead. I do schedule in time for myself. On weekdays, it's very, very early in the morning and very, very late at night. If works leaks over into the weekend, it happens. Not much I can do if that's the only time a client has for a consultation.
With your school and swimming though, that probably puts a dent in being spontaneous as well. You probably end up squeezing in the painting as much as I do, whenever possible.