God insists that we ask, not because He needs to know our situation, but because we need the spiritual discipline of asking.
-- Catherine Marshall

An omniscient God must know what we desire before we ask. God knows that what we really need most is reliance on God. And how do we develop reliance? Like most other things, by practicing.

If it weren't for the need to remind us daily or hourly that all power flows from our Creator, we could just say a quick prayer at the beginning of each week, or each year, and be done with it. Surely God could fill our requests a year ahead of time. But getting our wishes granted isn't the purpose of prayer. Getting to know God is the purpose.

I need to be in touch with my Creator every hour of the day.