3 - 12 hour days (or nights) sounds great, but they take their toll. I know people that would never swap from the norm 5 - 8 hour day (or night) shift for the tempting 3 - 12 hour shift.
For one... they see what it does to the people that work them.
And second... they like at least some normal functionally to their life.
Working 3 - 12 hour days or nights in a row is very much like one loooooong 72 hour continuous day. You do nothing for three days except work/sleep/work/sleep/work/sleep (if you're lucky). It is one very long stretch. And if you develop other issues, like sleeping or fatigue or attitude changes, or one of multiple health issues, then it can become unbearable.
Especially when working that long term, 3 years or more, and much more so working that during nights.
Most companies set up 12 hour shifts and pay for 40 hours. But is working three long days or nights worth it? And how long might it take to recover when your days off roll around?
If you work 3 - 12 hour days in a row, and more so on nights, your first day off will be basically sleeping. Sleeping most all the day. Trying to shake that spaced out hangover feeling.
And if you develop sleeping problems, then you are really in trouble. Prescription sleeping pills are all way too powerful. You become dependent very fast. After a short time they become less effective, and you need more and more. And the most popular brands prescribed will screw with your brain to the point you totally become another personality. Usually a mean, unhappy, detached from reality, personality. Just google AMBIEN, the most popular sleeping aid, and read all the horror stories.
There is nonsuch thing as using prescription sleeping pills on a temporary basis. That one day or night you skip the pill, you will not be able to sleep one minute. It will be like you drank 50 cups of coffee. Hopelessly wide awake.
Over the counter sleeping pills are just as bad. One day they might work, the next they don't. And regardless, that drugged zombie feeling can easily linger on with you for hours, when you should be awake and alert. There is no such thing as a magic sleeping pill. The side effects can be worse than the feeling of too little sleep.
But I think to work any 3 - 12 hour shift demands a lot of discipline.
Your best bet is to alter your life and try to maintain the same sleeping/waking schedule on your days off as with your days on. Very hard to do if that 12 hour shift is also a night shift. After time, especially a couple years, it becomes depressing having to sleep during the day, and then stay awake all night, when everyone else is asleep. You hardly ever see the sun, or if so, very little of it.
Then comes the real world.... Doctors and dentist just don't do 2am appointments.
If something comes along, appointments, car repairs, meetings, you will really suffer. Imagine if the "day" shift had to get up at 2am to go to an dentist appointment, or take the car in for service, or attend that special work meeting that everyone is required to attend. They just couldn't do it. But YOU, working that 12 hour night shift, YOU will be expected to flip flop you hours to accommodate.
One of the first things you will realize as a 12 hour night shift worker, is how little concern or sympathy those day people have for those night shift people. None!
And that includes your family members too.
I'd love to see those day orientated relatives get up at 2am to go on a family reunion picnic. Nada gona happen. Ever!
But YOU will be expected to party down when it's 2am on your time schedule....
I give working 12 hour shifts about 1 and 1/2 years before it drives you insane, and turns you into a drug dependent brain eating zombie-like walking dead, with no friends or family.