The most significant repairs are to Family Bibles. They are damaged because of their size & weight and then, as they are perused often, to view & add to the Family Tree. Worse, they can be stuffed with family mementos - hair, cards, photos or used as a press for leaves and flower.
Most come from the 1860's to 1880's and usually not always stored well through all the generations.
They have been found 'under the house', in an 'old trunk in the shed' and even fought over after family funerals which can result in family tree pages being removed!