As many as your ideas need, and not a single episode more.
In practice, though, we find that it’s helpful for listeners if you break down your show into seasons or cycles of either 10, 12, 13, or 23 episodes. This mimics the format that most broadcasters use, and it’s just a format that audiences have grown familiar with.
There’s no rule that says you can’t drop “season two” directly after “season one,” though.
Thinking about your show in “season” format is also really helpful when planning your content and preventing burnout. We’ve spoken with many aspiring podcasters who feel that starting an open-ended show seems overwhelming. Focusing on just your first ten or twelve episodes is a much easier way to get started.