OnShape is fairly generous with their free accounts with 100MB, but you can run over the limit quickly if you don’t know how to knock the file sizes down. OnShape saves a complete history of ALL your actions that adds up over time. If you save a copy of your document as outlined below, it will make a copy without the history. You will still have all the Features that define the objects, but the individual minute steps for all the odd steps you made along the way will be gone.