The best time varies
The best time to express milk varies from woman to woman. Your milk producing hormones are the highest at night, so a good time to express milk may be first thing in the morning
When to express
For a night feed – in the morning, as your breasts are fuller at this time
To relieve engorged breasts – little and often, before each feed for example. Be aware it can increase milk supply
To boost your milk supply – after daytime feeds