Oil on canvas is generally known to be a highly durable medium.
Short of direct trauma, it can withstand handling and extremes of temperature and humidity, as well as sun-light.
What makes one painting or sculpture more or less expensive than another in this primary market is usually size.
Although the artist’s audience has not yet rendered an opinion about which type of work is better or more desirable than any other, and the artist may feel some smaller works are better than some larger ones, usually size wins out, and the smallest works are usually the least expensive.
In addition, appliances and electronics have less value when succeeded by newer models.
When the real-estate market booms, the second owner of a home may pay more for it than the first, but in a stable market the second-hand house is likely to be worth less than a new one of the same size, design, materials, and location.
Most things we buy are worth less once we have used them.
A car usually is, as are clothes we give to charity.
Not so works on paper, which are usually priced lower to account for their greater fragility.
This has led to the notion that works on paper are inherently worth less than paintings, despite the fact that the secondary market in some cases has placed a higher value on works on paper than on oils by certain artists, such as Edgar Degas and Mary Cassatt.