Elder Ieronymos of Aigina :

Do not go to sleep without prayer. No matter how exhausted you are, pray --  even if it is in bed – for at least half an hour. When you have your mind in God, then –wherever you find yourself, on the road, at home, in bed – you are able to pray. Whereas when your mind runs elsewhere, then – even if you are in church –compunction will not come; and your prayer will formal and dry.