This is a question that gets asked all the times and the answer comes down to how regular and often you can work on your voice. Fortnightly lessons are generally the best time frame. It’s enough time to work on the exercises from the past lesson and means that things can start to develop too before coming back for a top up of exercises.
Saying that, every singing lesson gets recorded and the exercises are sent to you via email. These exercises are obviously totally tailored to your voice. The more regularly you do these, in your own time, the quicker your voice is going to develop and therefore, the less frequently you’d need to book in.
Everybody is different, everybody’s goals are different and therefore the answer lies with you. To summarise, the more time you spend working on your voice in your own time, the quicker you’re going to feel progression.