Seriously - this question is way too broad to give just a pat answer. If you are a professional singer, there is a lot of practicing involved each day in order to get ready for their next performance.
If you sing in your church choir, then they usually have rehearsals once or twice a week.
There are many singers that vocal lessons to keep their voice in tune without straining and many that record their music but are not a fan of tours, so their practices might be less. So you need to pin down what you are looking for and research that.