If their work is isolated and can be paused while they're gone, it doesn't matter. Well, other than dropping productivity for that duration.
But for most of us, we're operating as part of a team. Our duties don't stop when we're gone. They have to be covered by someone else. If I'm disappearing for a month, the rest of the team will have to pick up the slack and do my job for me.
This might be okay if you're working on mythical man-month projects where the work can be redistributed and deadlines pushed back at will, but at most companies it just means everyone else has to work harder to cover.
If someone wants to come and go for months at a time, it's better to restructure their employment as a contractor and provide the work in contractor-sized blocks. Full-time employees are expected to make an effort to be available full-time for the team's sake (excluding emergencies and such)
But for most of us, we're operating as part of a team. Our duties don't stop when we're gone. They have to be covered by someone else. If I'm disappearing for a month, the rest of the team will have to pick up the slack and do my job for me.
This might be okay if you're working on mythical man-month projects where the work can be redistributed and deadlines pushed back at will, but at most companies it just means everyone else has to work harder to cover.
If someone wants to come and go for months at a time, it's better to restructure their employment as a contractor and provide the work in contractor-sized blocks. Full-time employees are expected to make an effort to be available full-time for the team's sake (excluding emergencies and such)