Approximately 40 years. His approximate age when he had the experience at Mt Sinai and received the Ten Commandments was in his early 80s. At 120 according to other sources he climbed to the top of Mt. Nebo, saw the promised land and died. So, it would be exactly forty years if he was exactly 80 when he received the tablets. But it would be slightly fewer years if he was in his early 80s. Best estimation 35-40 years.
The commandments were all given in Moses' life, but their application stretches all the way to the present.
Moses Hirschel died in 1823.
Lee Moses died in 1997.
Moses Coady died in 1957.
Moses Quinby died in 1875.
Moses Rawlings died in 1809.
Harry Moses died in 1938.
Moses Sheppard died in 1857.
Moses Allen died in 1779.
Moses Bloom died in 1893.
Moses Samuel died in 1860.
Moses Carter died in 1860.