The caption for a post is important on any social media platform, especially on Instagram. However, you want to make sure you get the information across without creating a wordy post.
Whilst Instagram has a maximum limit of 2200 characters, roughly 350 to 550 words, you want to aim below this level. Whilst not every post needs to be 1 line long, look towards being easy-to-read.
Make sure to not let every word be in a block of text and look to get your information across quickly and easily, so as to keep your readers eye.