The 71-year-old took to Twitter to share how the industry has changed over time.
"Future producer says match your dates with the window given by the other in film...Time was when others matched dates with mine," Amitabh posted on the microblogging site on Saturday.
The actor, who is currently shooting for "Bhootnath Returns", made his debut with the 1969 film "Saat Hindustani".
Over the years, he has entertained movie buffs with films like "Sholay", "Kabhie Kabhie", "Adalat" and more recently, with films like "Kabhi Khushi Kabhie Gham","Cheeni Kum", "Bhoothnath" and "Satyagraha". Last year, he made his foray into Hollywood with a role in "The Great Gatsby".