Anthony writes:
Viewport performance is important for everything, but if one is trying to preview some character animation, then being able to see it in real-time (24 to 30 fps) is critical.
Now you can always just render out a quick playblast, but that still takes time and is no good if you need to go back and forth while adjusting the timing of a specific action.
At the same time, you can make/use really simple proxies, but for the most part you still need some level of accurate visual presentation while animating and viewing the result.
In my latest video I go through some tips and techniques on how to achieve 30 fps playback of a character in the viewport.