The Spanish international goalkeeper reached the landmark figure in Saturday's thrilling 3-2 triumph at Malaga.
But mere statistics do not impress the talented shot-stopper, who is adamant he is not focused on making hundreds of appearances.
The 21-year-old is merely concerned with enjoying his football and will have no regrets bidding farewell when he no longer feels fulfilled.
Casillas also acknowledges his spell on the substitutes' bench last season helped him to become a more mature player.
"I do not consider playing in 500, 600 or 700 games," said Casillas.
"I only want to enjoy every day and until that happens I will continue playing. The day I don't enjoy it, I will have to say so long.
"One of the worst memories I have is when they put me on the bench for a time.
"It took me by surprise and I tried to come to terms with it but that helped me to mature as a football player."
