If you want to adjust the entire animation timing, a scale transformation
is the best choice. Press the A key to select all keyframes and use the S
key to scale up or down animation as the whole (Figure 7.15).
Figure 7.15 - Timing the entire animation
By using a scale transformation, you must be careful with the current
frame. That frame works as the pivot point for the scale. To keep your
animation starting in the same frame, make sure you set the current
frame as the first one from your animation, before pressing the S key.
Using any other frame as the current frame during a scale might
completely change your animation's Start and End frames.
Tip: You can also use the Snap at the Timeline Editor. Select a keyframe
and press SHIFT+S to show options related to animation.