Luke18:1-8
1. Becos God commanded us to pray. You don't pray enuff until you see d answer. The moment you stop praying, you've started fainting. Rom 12:12, Eph6:18. James5:13: is any among you afflicted, let him pray.
2. Because when you faint, you get nothing. D only why you can pray effectively is becos there is provision in place already. Jeremiah29:11-12. Prayer is partnership with God to accomplish what He's said He'll do in our lives. Galatians6:9
3. Its because answers to prayers are guaranteed.... Ask & you shall receive, seek & you shall find. And so if you give up, it won't be d devil's fault you didn't get ur answer but becos you fainted.
4. So that your faith will not fail. Luke 22:31-32. One of the things dt guarantee ur faith fail not is prayer. When your faith is strong there is enthusiasism, there is zest.
5. Becos it keeps the enemy at bay. This doesn't mean the enemy will not keep on with his operations, its just that they'll not be accomplished. In prayer, we are delivered from evil.
6. Its a means of escape from perilous times. Luke21:34-36. We must learn to keep watch & pray. Its prayer that keeps our heart tender.
7. By prayer, we make things happen. 1Cor2:5-13...we speak things that make things happen by prayer. We need 2 know what it is 2 make things happen.
8. By prayer, we stay spiritually opt. We keep our spiritual fervor. Jude1:20
9. Prayer is an expression of our faith.
Jeremiah19:19-20
1Tim2:1-4

1 great reason to stop praying;

The OP has missed it totally..unless God is deaf or book-haram have blown heaven's masts. By Jove God is no deaf for Christ sake.or is he