Free time is something we all should make room for, in our days.
Not on days when there are less items to cross.
Rather every day, even on the busiest ones.

Read books.
Practise a skill you are inclined towards.
Or just do nothing and be alone.

It is not time wasted.
Rather if we do not make free time, the “productive” time would be longer, hazy and even confusing. 

Most of life is to maximize our free time.