Voice students usually practice 2 hours a day or more. That doesn't include time spent learning to sing at first sight, dictating, playing the piano, and absorbing knowledge related to singing, such as anatomy, music theory, and music history. If you want to make changes to your voice in a few months, practice as often as possible. For example, if you have never sung before and have just started vocal classes, doing 3 hours of practice will not benefit you: the muscles in your voice are not strong enough to hold up to 3 hours of exercise.
But what is more important, is it true? Should you practice every day when it comes to learning a musical instrument, in this case, your voice? Will your voice and reach improve?.