How many times a night should I play a recording?

Once is enough. I haven't seen any differences in effectiveness or immediacy of results based on repetitive listening. Some people listen only once. Some people play the recording over and over all night.

One engineer hooked up three machines to each other - so one machine triggered the next. He played three 90 minute tapes each night, all night long. However, we couldn't identify any added benefits with his system.

Can I play the CD during the day? in the car?

Do not play it in the car. It begins with a go-to-sleep introduction!

You can play a CD during the day, but listening while you're in the beta brain state doesn't provide any benefit.

Playing it while you sleep during your theta brainwave state -- twilight and sleep time -- by-passes the conscious defense mechanisms, reaches a different part of your brain, and creates change at the deepest levels.

If you are listening to a CD with a significant issue for you on it, you probably don't want to hear it awake. Your goal is to change things on a subconscious level easily and effortlessly. There is no reason to process your past while you are awake -- when you can simply sleep through it.