[cookiecaper]

It depends on the expectations of the employer. This stuff is usually stated on remote job listings (though admittedly jobs that start as "choose your own hours" somehow transition to "work between 9 and 5 Pacific time" too frequently). There are remote employers that expect you to be continually available for instant comms all day, part of the day, or none of the day (i.e., unscheduled instant comms are non-mandatory). The latter is obviously ideal but also the most rare.