Low quality paper becomes fragile due to acids reacting to sunlight (paper destroys itself). Artist papers are acid-free and should ideally consist of cotton rags. When buying paper one should pay attention that it is ph-neutral and that it carries the designation, resistant to ageing. "Ordinary paper" is made from cellulose and has a high percentage of wastepaper.
Artwork should be protected from direct sunlight, dirt, dust, changes in room temperatures and humidity. This can be done by preserving the piece under glass and placed in a dry area where direct sunlight does not come in contact with it.