The numeric value of “How many frames are renewed per second” by application is called “FPS (Frame Per Second)”, and this “one renewal” is called “one frame”. This “one frame” becomes “the least unit time” when animation is renewed.
When it is said “30FPS”, it means “The frame is renewed 30 times per second”. “One frame” of that instance becomes “approximately 0.0333 second (The value: 1 second is divided by the number of FPS)”. When animation is created, it is better to create with the same FPS as the FPS expected on the hardware on which application operates. Also, the length of animation itself may better consider FPS.
Regarding these matters, refer to the after-mentioned “About the relationship between FPS and the “Animation Length” and the “Key-Frame Position”. If the FPS upon animation’s playing is unstable, the state of animation’s regeneration play also becomes unstable. So, caution must be taken.