When it comes to using new designs on American coins, the United States Mint is known for having a conservative approach.
The evidence is obvious: Most U.S. coin designs don’t change with any frequency.
The Roosevelt dime, for instance, has remained unchanged since it first appeared in 1946. The Jefferson nickel (1938) and Washington quarter (1932) both debuted in the 1930s and saw very little variation until the 21st century. Although the Lincoln penny got a new reverse design in 1959 (and again in 2010), it has also been largely the same since it was introduced in 1909.