To try to mitigate this, property expert Mehran Charania suggests some simple mistakes to avoid - which could possibly save thousands in fines, double payments and move day mishaps. The expert from storage firm Ready Steady Store believes the most costly mistake could lie in your home and contents insurance small print. A property guru has revealed the simple mistakes that could cost you THOUSANDS during the 'most stressful part of life' - moving house. She adds that another common mover mistake is forgetting to cancel or transfer household bills, leading to frustrating double payments. Another mistake that can cost you more than £1,000 is to get caught out with your first month mortgage payment.