This is a great question for artists to put forward, but there isn’t one exact answer. In fact, depending on who is asked, very different answers will be given.
Heat on the Street suggests that releasing one new track every three months is a minimum to ensure the online algorithms built into sites like Spotify and others don’t begin punishing you in some ways.
The Ghost Production suggests one one song every month, which adds up to essentially an album a year.
A blog posted by Spotify for Artists quotes Anthony Martini, head of Commission Music as saying, ”You definitely want to have new music of some sort every six months or so. It keeps fans active, the algorithm stoked, and helps to continue growth.” Elsewhere in that piece, it’s suggested that the time in between full albums should be 18 months to two years.