Whilst everyone is working or living in a building, that building is degrading itself by the weather and fair wear and tear, building settlement and subsidence which is occurring 24 hours per day. Plus insect and pests molestation damage to the external and internal structure of the building which eventually shows up on external damages to the building. Insects and pests are quite a big source of damage in a building as they eat anything, including electrical cables, concrete, wooden elements, plastic elements, that they come across, and give.
So preventative maintenance must be carried out, with regular time period audits of the buildings structure. Ground settlement is occurring all the time 24 hours per day, and may give rise to structural stresses and strains in a building to cause cracks or even foundations failures.
There have been cases of buildings external cladding falling off and hitting passers-by, causing pricey legal cases. Plus if pests, etc, block water drains and the resultant water back-up, rots through the foundations of the building structure, severe external damages will be the result.