"We are indoctrinated with an idea that time needs to be "spent". That's why you wonder what people do when they don't do all the things you do. I tell you what: they engage with others and, more importantly, with themselves. They learn who they are and what they value. Without any effort their minds plan the future and consolidate memories of the past.
That, I think, means to be truly alive. "The unexamined life is not worth living," said Socrates. The modern version is maybe this:
The person that lives solely in emotions and information from the outside, the person that never pulls itself out of this messy reality and gives itself over to a mental spa, a time of healing and processing, a time of reflecting, feeling, thinking, seeing, worrying, planning, smiling, that person doesn't live."