By the weekend all buildings (except special government-owned ones) will begin to decay over time, reducing their productivity and eventually disappearing from the world.
Normal decay is very small and it'll take around 160 game-years for a building to completely decay, however the rate will increase significantly (10x) if it is not being used (i.e. Owner does not have the required skill to make the building function) and even more so (100x) if the building has no owner. (i.e When a player dies, any buildings they owned will disappear from the world after 3 or 4 real-time days if they are not purchased by someone else).
You can pay to repair damaged buildings, the cost being proportional to the amount of decay to repair and the original cost of the building.
Separately, there will be a change to the rules concerning death and stocks : When someone dies, all building stores and investment will be removed before the building is put up for sale.