This is a question I've seen many artists; especially new ones are struggling to find the answer. Some love to release a song each few days and some believe only in "perfection" and they don't hesitate to work even a year or two on just one single track before releasing it. But the main question is that how often to release songs and albums to be active enough yet not to be a spammer!
Well, when it comes to such topic, there's no right or wrong and it's really up to the personal mindset for indie artists or the managers of label for signed artists. And here is my personal opinion based on my 15 years of experience:
There are a lot of people approaching me or respond to my approach for either publishing their music or using their demos for pitching to the bigger names in the industry. I can say about 40% of the demos are receive are okay in sense of professionalism but the other 60% usually have some sort of issue which makes the project to don't move forward. Here I list down some of the common issues and the solutions for them.
Decide what you want. Before sending your track or your demos to a publisher or a producer, make sure at least you know what you want, and it would be even much better if also be open for their suggestions too. When you are sending them a demo, do you something in mind? If you had the power to get the song in whatever direction that you wanted, what would you do with it? All these and things like these are what you need to prepare before sending your demos out. Don't be confusing and don't make people confused. At the end of the day, this is your project and you want it to move forward, right?