How long does it take to tell?

[PlasmaAstralProjection]

If a AP technique works how long should it take to tell if it works for you? If indeed it is the right one for you. Thank you.

[Xanth]

It takes as long as it takes. 

As a general rule of thumb for myself, I try for 30 minutes.
If after that time, I feel that it's not going to happen or if I just can't relax enough... I stop and go do something else.

Last night for instance, I was trying to meditate and get in a bit of phasing practice too, but my dogs kept whining.
I went to another room to escape them, but it was all for nothing... 15 minutes went by and I just couldn't get into that zone.  So I stopped.

[Stookie]

If a AP technique works how long should it take to tell if it works for you?

I would practice for a minimum of 2 weeks at first to get comfortable with it. If at the end of 2 weeks you just don't feel it, try another one. If you are comfortable with it (but not necessarily getting any results), stick with it for as long as you can. If you're doing it correctly, then it will eventually happen. It may take a while, but you have to stick with it. Don't switch techniques until you've fully tried it out over time.