Whenever I am lazy, I tell my wife this: "Everything will happen according to God's will and so I am not inclined to pray. I cannot change God's will through prayer".
It is true, God's will cannot be changed through prayer. Job realized this the hard way here:
I know that you can do all things, and that no purpose of yours can be thwarted. ‘Who is this that hides counsel without knowledge?’ Therefore I have uttered what I did not understand, things too wonderful for me, which I did not know. ‘Hear, and I will speak; I will question you, and you make it known to me.’ I had heard of you by the hearing of the ear, but now my eye sees you; therefore I despise myself and repent in dust and ashes. Job 42-2:6
If we think we can alter God's will through prayer, then we got the idea of prayer really wrong. Prayer is for us to overcome our own fleshly will, and is never about changing God's will. In fact, it is the will of God that we should pray and overcome our own fleshly will. If you note Job's statement above he says "I have uttered what I did not understand, things too wonderful for me, which I did not know". Think about a man who lost everything. A man who is suffering pain through sudden illness. Yet he says he does not know what to utter before the LORD. This is perhaps why we needed the Holy Spirit to pray for us as said below:
Likewise the Spirit helps us in our weakness. For we do not know what to pray for as we ought, but the Spirit himself intercedes for us with groanings too deep for words. Rom 8:26
If we do not know how to pray, then why should we spend hours in prayer? To add to that it seems it is possible for our spirit to pray while our mind is fruitless.
For if I pray in a tongue, my spirit prays but my mind is unfruitful. 1 Cor 14:14However, the Bible instructs us to pray without ceasing (1 Thes 5:17). We can never forget when our LORD prayed in the garden of Gethsemane:
Right here our LORD instructs us to pray:My Father, if it be possible, let this cup pass from me; nevertheless, not as I will, but as you will. Matt 26:39
Watch and pray that you may not enter into temptation. The spirit indeed is willing, but the flesh is weak. Mat 26:41
All this means, first we need to have a prayerful mind. If we have a prayerful mind, we will confess our own fleshly desire. Jesus himself confessed that He wanted the cup of the cross to pass away from Him. He confessed, "My soul is very sorrowful, even to death" (Matt 26:38) This confession sets the stage for our Father to work in us. Jesus did struggle in the garden of Gethsemane but came out victorious saying this:
My Father, if this cannot pass unless I drink it, your will be done. Matt 26:42
The simplest prayer that we should say is "...your will be done, on earth as it is in heaven" (Matt 6:10) But if we say this without conviction we will become hypocrites. We will have to pour out our heart to God. We will have to confess our fleshly desire like how Hannah did before the birth of Samuel.
No, my lord, I am a woman troubled in spirit. I have drunk neither wine nor strong drink, but I have been pouring out my soul before the LORD. Do not regard your servant as a worthless woman, for all along I have been speaking out of my great anxiety and vexation. 1 Sam 15-16
Hannah has been confessing her desire and realized it is the LORD's will for Samuel to be born. This confession and transformation from our fleshly desire to Spirit-filled submission is true prayer. This is the part that takes time and we need to spend time. It is one thing to say let the LORD's will be done, but it is you who will be the stumbling block for the LORD's will to be done and it is you who will have to submit to the LORD's will. This cannot happen without spending time in prayer. Prayer is walking with God and without prayer, it is impossible to walk with God.