Forex New fibonacci retracement lines - where and when?

Hi all,

Happy weekend.

A quick one --

I've been trading (a small account) on and off for a little while, with relatively flat success, and I have recently stumbled into the world of fibonacci retracement. I have used it with fair success this week (GBP/USD), but now the swing low that I had pinned the end of the bar to has been broken, I wondered what the protocol was to give up relying on that existing set up and draw a new retracement line.

Is it a case of waiting for a new significant low, is it a moveable feast, etc?

Many thanks for any responses, in advance.

Source.