Lists.

When moving, do make a list of items that you really can't do without as it may come as a huge shock when you realise that you can't use your laptop as the battery needs recharging and the recharger is in another country and the house that you have just left is rapidly being emptied by your son.  The same applies when your GSM finally lets out its last signal before going completely blank and dies in the palm of your hand.  You may think that you packed your GSM recharger, but, after emptying your suitcase and throwing clothes all around someone else's bedroom only to find that the lifeline to your GSM is also in another country, it soon becomes apparent that the only useful bit of your phone is the SIM card.

Other bits and bobs that you may leave behind are extremely useful and long extension cables, ideal for lawn mowers, tweezers, wellies (found them - in storage), headphones, office chair, laptop rest, mouse (two - TWO), various kitchen utensils, kettle, full box of tea bags, wine racks....

I know that this list will get longer, much to my chagrin.