The amount of breathing space varies depending on which pair you are trading and the amount of risk you are taking, so there is no simple answer. One week a pair may be averaging 100 pips a day movement, the following week that could drop to 50 or increase to 200 depending on what has happened and what news events are coming up. Likewise, if you dont want to increase your risk, you could reduce your lot size to allow you to take a bigger pip loss risk without adversely affecting your account