know that feeling, that its just a bit too fast or halfway the action is a bit to slow… ?
Or maybe everything is a bit to slow, or to fast, and you like to keep the same frame rate ?
Goto Blenders animation screen, there is a panel called dope sheet.
From there you can select all the items that you have animated, and it uses pretty much the same old blender keys.
So you can use B key for a border select around a group of animated elements, or just select as in edit screens.
Next you can simply Move (G key) or Scale (S key) those selected animation actions over your time line there.
Dont like robotic movements?,
Be sure not to put all your changes (rotation location) of multiple objects / bones at the same keyframe.