Three reasons to animate
Continuity — showing where an element came from. Hierarchy — telling the eye what to read first. Explanation — demonstrating a process that a static image would flatten.
If a proposed animation does none of those three, we cut it.
One timing language
Pick one easing curve and two or three durations for the entire product. Inconsistent timing is what makes an interface feel assembled rather than designed.
Performance is part of the craft
Transform and opacity only, respect reduced-motion preferences, and test on a mid-range phone. Motion that stutters reads as broken, however elegant it looked in the file.