If you are brand new to the game (i.e., have your default weapon + bomb) and are playing solo, you should probably extract after level 2. If you are quite good at the game, you might be able to make it through level 3.

As you continue to improve your equipment and abilities, you will get a better sense of how much additional progression this allows you to make, but don’t forget that you lose all items in your bag if you die in the dungeon.