Good question. Some smokers and drug users are indeed delivered promptly With others it occurs over time. Why the difference?
I echo the view of others. If God delivered some believers this way they might take it for granted. They might treat it too lightly. Some could think, “Hey, if I backslide, I can just pray a quick prayer and get delivered instantly.”
One man said that he had stopped smoking “many times.” God does not want us to play with sin. It was big pain for Jesus to die for our sins. Humility and appreciation for this will take it seriously. This includes learning to cling to Jesus, our deliverer, our victory, daily. This is walking by faith in HIS power, not our own. We do not get so delivered, that we no longer need Jesus’ help with temptations.
“I am the vine, you are the branches; he who abides in Me, and I in him, he bears much fruit; for apart from Me you can do nothing.” (Jn 15.5 NAS) (Jm 4.7; Jer 29.13).
A second possibility for not getting delivered is that one is still outside God’s family of faith. They are still on the run from salvation. They only want to go on a temporary sin diet. Jesus cares for their eternal soul above all! Some treat redemption as an optional extra – not so. For example, many lost sinners will go to hell that were never drug addicts.