Pray frequently and effectually; I had rather your prayers should be often than long.
Jeremy Taylor, 17th c.

We can fall into the trap of thinking there is a direct proportionality to the time I spend in prayer and its "effectiveness." But that is already a misunderstanding of prayer. We do not approach our Father to earn his favor by our words; he is already gracious towards us and delights in us for we are his children. Prayer, rather, is communion with him. It is being in his presence. Sometimes words do this. Sometimes it may be meditation on Scripture. Sometimes it may simply be "Amen." But as we dare not forego breathing too long for in so doing we deprive ourself of the wind of life, so we should not forego prayer for too long. Just as we need not take every breath as deeply as possible–we may end up being a bit light-headed in fact if we attempt that!–so too every prayer need not be as long as possible. To quote Taylor again, "I had rather your prayers should be often than long."

For some of us, our prayers may be the entire Office (or Offices in the Book of Common Prayer) with all corresponding readings and several collects, too. For others, our time is restricted due to late work shifts, tired children, or other responsibilities. And though we feel the limits of our time, we are a people praying often. We need not pray long. But pray often. This may look like praying the Lord's Prayer for Morning and Evening Prayer. It could look like including the Psalm for that Office if you have a few more minutes. It may look like praying the Jesus prayer: "Lord Jesus Christ, Son of God, have mercy on me, a sinner."

We must start where we are and certainly hope that growth will happen by the Spirit of God. But we need to start where we are. For you have need to breathe by the Spirit of God and to do so often.