There is no fixed duration for an animation. In general, our animations last one minute. And practice shows that this is an effective duration.
However, we always advise you to look at how you are going to use the video and the target audience you are trying reach. Younger target audiences, for example, have a shorter attention span than the elderly. And during a presentation a video should be longer than on social media.
So, let's discuss how you want to use your animation. And who the target group is. Then we can give you advice for the duration of your animation.