I like to close my trades 15 minutes prior to the 5:00 PM NY Session close. This rule is to avoid the expanded spreads on pretty much all currency pairs around the close of the New York session / open of the Asian session.
The Asian session is known to be a very low volume trading time. Because of that, we try to stay away from the expectation that price would remain in the direction of our intended move during the Asian session.
The risk of the new session going to seek out more liquidity before driving further in our direction also remains. Therefore, exiting any open position is one of the ways we try to secure unrealized gains.
Below is a KIWI (NZD/USD) long trade where I exited using the end of day trading rule.