Castors (or casters) allow people to move large, heavy objects easily from place to place. These wheels come in different sizes and types. Objects that must move in a straight line, such as a shopping cart, use rigid casters. Dolly carts and heavy equipment use industrial casters, which can support immense loads.
Life without this device can certainly be difficult. Next time you need to move a heavy item, save time and effort with some properly-placed castors.