How many years does calligraphy need to be practiced?

Some people are retired and don't know what to do. They can practice calligraphy. How many years does calligraphy need to be practiced? This is different according to everyone's talent. Generally speaking, calligraphy will achieve some results between 1 year and 3 years. You must practice every day and read some inscriptions and copybooks every day. Practicing calligraphy can also adjust the mentality.