There are a lot of things to do when moving. And you could be very busy that you would not be able to keep track where each item goes. The solution to this is having an inventory of all your things. You should list down each item as you put it inside the box so you will not miss anything. It would also be better if all boxes are labeled with a list of the contents and its destination so you or the movers would know where everything is supposed to go. With an inventory in hand, finding any specific item later on would be easier.
Of course, if movers are going to handle your boxes the inventory will help you ensure that everything will get to your new place. It would be better to take photos of each item too to have a proof of their condition before transit. If anything gets damaged or broken, it would be easier to make a claim. You would be ready even for extreme cases when the movers get your things burned or stolen. You will know what items were loaded to their vehicle. So again, you would have a proof so getting a claim would be easier for you.
