Praying with Persistence or Shut Up and Trust

How are we to know when to keep praying with persistence about the same thing or when to shut up and trust that God has heard us and move on?

As a parent I have kids who constantly are asking for stuff, to have stuff, to do stuff, to get stuff... always wanting stuff. My youngest who is seven at this time is dying for her own email account. We have told her to wait and we would set it up when we thought she was really able to handle one. However, even though we have already given her an answer which was to wait, she continues to constantly come to us and ask "But when?"
To which we have chosen to reply, "Every time you ask the time gets pushed back further."

Hmmmmmm, now I wonder, is that my Father's reply to me as well?

You see I ask for stuff, to have stuff, to do stuff, to get stuff... always stuff. It's all reasonable stuff. Our house to sell. Foreign mission trips. Book sales. Ministry opportunities. Financial issues. Confirmations of prayers. You know good reasonable stuff.
And I have heard Him many times give me the answer, "Wait and I will give it to you when I know you are really able to handle it."
However, I still find myself constantly coming to Him and asking, "But when?"

So I wonder is God looking at me and saying "Every time you ask the time gets pushed back further."?

I try to justify my constant "But when's" with the parable of the widow before the unrighteous judge in Luke 18:1-8, but my request are not going up before an unrighteous judge are they...

"Now He was telling them a parable to show that at all times they ought to pray and not lose heart," (Luke 18:1)

So how do we know when to be persistent in prayer and when to shut up and trust?

I'm still working on this one, but I think when the prayer is actually a whine... it's probably time to shut up and trust. If I am whining, have I lost heart? Is a whine even really a prayer request? I tell my own children, "Excuse me, but I don't understand whine language, when you can address me in english, we'll talk."

So if I am whining am I really trying to emotionally manipulate God? (Like that's going to work!) Am I really just doubting that He heard me or is going to do what He said He would do? Is it that I am not trusting that He has my best interest in mind at all times? 

"will not God bring about about justice for His elect who cry to Him day and night, and will He delay long over them? I tell you that He will bring about justice for them quickly. However, when the Son of man comes, will He find faith on the earth?" (Luke 18:7-8) 

God is not going to delay in answering my request, even if and especially if the answer is wait. He will bring about His will quickly, as He said He would. Did you know that this word "quickly" is showed as only being used seven times in the Bible by the NAS Greek Lexicon?  In Luke 18:8, Acts 12:7, 22:18, 25:4, Romans 16:20, and Revelation 1:1, 22:16. The word is tachos in the greek and it means quickness, speed.

Perhaps what God is telling us many times, is wait, and when I answer I will answer with quickness and speed. You will have no doubt that it is Me. No doubt that your prayer has been answered according to My will to accomplish My purpose in you. So My dear precious one, My beloved, when I come with My answer to your request, will I find you waiting in faith...

So are we to pray with persistence or shut up and trust?
I think the answer just might be both.
A little phrase that I have coined... "when in doubt, pray about"

However, maybe, NO WHINE LANGUAGE ALLOWED :-)

This is the confidence which we have before Him, that, if we ask anything according to His will, He hears us. (1 John 5:14)