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 Quinby died in 1875.
Moses Bloom died in 1893.
Moses Benson died in 1806.
Moses Mielziner died in 1903.
Felix Moses died in 1888.
Moses A. McCoid died in 1904.
Moses Hampton died in 1878.
Moses Buttenweiser died in 1939.
Moses Hirschel died in 1823.
Lee Moses died in 1997.
Moses Carter died in 1860.