I think I'm selling mine when they go under 400$, which I hope will never happen, but might even happen today the way it's going down now.
On the other side I think I will sell them at around 900$
I won't ever sell them under 400$ because that is too small price to sell for, 900$ might be a good time to sell bitcoins
Personally i think that i will sell if price will go to more than 800$, because i bought my bitcoins for 430$ so selling for 700$ will give me profit for sure