system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do TV shows like "House of Cards" have different directors for each episode?
gpt
Principal photography (filming the actors etc.) may only take a week or so (depending on the show), but there's always weeks of pre-production (location scouting, script revisions etc.) and post-production (audio re-recording, any special effects) that the director is involved in (they're not doing all the work, but they have creative input.)

Principal filming is a full time, 10+ hr days affair. It would be challenging for a director to handle that, and also handle several hours/day of pre- and post- production for previous or subsequent episodes, so they spread the workload around.

Or, as the producers/show-runners, you may have an episode that calls for a particular skillset. Like the episode deals with a tricky subject matter or has a challenging action sequence and you know that a particular director has the skillset to translate that well into film.