Day-to-day deterioration is a term used to describe the gradual decline of something over time. It is often used to refer to physical objects, such as clothing, which can become worn and tattered due to regular use. The crossword solutions for this term are WEAR, which is a verb meaning to suffer gradual decline or damage due to use or exposure. This term is often used to describe the effects of aging, as well as the effects of regular use on physical objects.