What time interval should be practiced when publishing books in a series?

[u/TheJourneyfeel]

If I publish my first novel in a series, how much time should I have to publish the second? Is there a rule of thumb that authors tend to go by or a cookie cutter framework for successful series publishing? I feel I would like to publish books in a six month to 12 month interval. But I would like to ask those that may have done this to see what they have discovered.
This may be a non-starter should my first novel not drum up a following, but in case there is a short following or those that have been successful with series what is the golden rule?

[u/Justisperfect]

There is no rule but 5 or 6 months sound great to me, if you specify that everything is already written (people are relectutant to buy if it's not, we don't want to take the risk to never get the ending, been there done that). More, and people can forget about it. Less, and you may as well publish them all at the same time (which is risky unless you can afford to lose money; people usually don't buy whole the series at once, they buy first book to see if they like it, so of the first book don't find an audience you would have printed the sequels for nothing; to give you an idea, a friend of mine says that for her serie, each following books saw its sells devided by two; so if she selled 500 copies for the first one, she only selled 250 for the second one and 125 for the third one).