Chapter releases should be based off two factors.
The first is book age. If it's a new story, you'll want to sort of "spam" out chapters. More chapters during the initial posting to take advantage of visibility.
After that, it should be based off "word count". I say that in quotations because stories with shorter chapters should be more proactively posted because they should be quicker to write, proofread, edit, and post. Longer chapters will obviously take longer to write and prep for viewing.
However, if your life dictates otherwise, then do what you are comfortable with. Your readers will adapt.