Risk-on, risk-off: what does that mean in practice?

On "risk-on" days traders buy growth-linked currencies and sell safe havens; on "risk-off" days the whole trade reverses. The terms sound simple but the behaviour underneath is messy and changes over time.

For beginners:

• how do you tell whether today is risk-on or risk-off?
• which pairs do you watch to read the mood?
• have you been caught assuming the pattern still held when it didn't?

The risk-on risk-off guide explains the concept and its limits.