We so often speak of spiritual disciplines singularly that we can easily forget in practice they naturally flow one to another.
In the small volume of devotions, Challenge by Mark Link, S.J., he offers the following pattern for those going through the book: (1) Read the reflection prayerfully. (About one minute.) (2) Think about what stuck you most. (About four minutes.) (3) Speak to God about your thoughts. (About one minute.) (4) Listen to God’s response. Simply rest in God’s presence with an open mind and an open heart. (About four minutes.) (5) End each reflection by praying the Lord’s Prayer slowly and reverently.
Then on a Ron Edmondson’s web site I saw the counsel that in a daily quiet time of 15 minutes you could, “spend 6 minutes reading the Bible, 3 minutes talking to God, 2 minutes in silence, asking God to speak to you, and 4 minutes writing your thoughts at the time.”
http://www.ronedmondson.com/2011/07/how-to-begin-a-daily-quiet-time-in-5-easy-steps.html
Though these two writers come from different traditions they both recognize silence needs to part of one’s practice. I will not presume to tell you how much time you should spend in silence, but I will be be presumptuous enough to say you need to find time in your life for silence.