I read the KJV daily for instruction before each day starts. I used to do one reading in Psalms and Proverbs each, which ministered to me greatly and God used the Word to guide me as I went about my day. At another's suggestion, I went to a daily bible reading guide, but now may switch back to my original format. I miss the way God interacted with me through these 2 books.
I study otherwise on a certain theme, which is what works for me. I listen to sermons via podcasts and take scripture from those to further study. Sometimes this leads to a new theme or topic and then I start studying in that direction.
If you are looking for quantity, I would have to say...always. This is due to the Holy Spirit, Who guides my studying, reveals truths, and draws me closer to the Father and to being more Christlike. I never used to say that because I was not always hungry for God's word as I now am. When I am not reading, I am meditating on His word. It has come to this and I waited a long time to experience this closeness with God.