Hi my husband has been prescribed 24/7 oxygen. He has a concentrator in the house and two small tanks that last about 3hrs each. How do others manage o2 outside the house, particularly for longer trips? how often do you order new tanks? He is seeing his consultant again in January and fingers crossed he will only need the oxygen for a short while to recover from a couple of nasty infections but if not do you recommend a portable concentrator? Sorry for all the questions but we are very new to this.