Would you invite someone you do not know very well into your home to sleep in your private space? Well why would you chose that person to share a hotel room with you for 3 weeks when travelling in a foreign country?
Yes the cost of twin share to single is a big saving but I do not think it is worth the irritation and the stress that could eventuate by living with a person 24/7 who turns out to be the travel partner from hell!!. It is an unknown factor that could turn either way when you are in the middle of your trip of a lifetime.
Travel only with long time, well worn friends who you can have a good argument with and then hug and make up. Imagine travelling for a week with someone who is not speaking to you? This could completely ruin your trip and your memories of it for ever more.
