I was raised a JW, and baptized at 15 yrs old. I married at 19 and spent 4 years getting steadily more miserable, by which time I did not care whether it was the truth or not, I just could not carry on. So there was never a plan, just one night I knew the time had come to escape. It took about an hour to pack, and I never went back, and never saw a JC. They disfellowshipped me in my absence because I did not want to see the elders (petrified I would be persuaded to come back).
So, about 1 hour is how long it took me.
However, mind and heart did not really escape until I researched on the internet and found out the history of failed prophecies, Jerusalem not destryed in 607BC, and so on. Thank you H2O!