@elmo.conroy
It depends on the specific use case and personal preference.
A sub-domain can be useful if you want to keep all of your assets, such as images and videos, organized within the same main domain, while keeping the sub-domain separate. For example, you could have a sub-domain like "static.example.com" that serves all of your static assets.
On the other hand, hosting your static contents on a different domain can improve performance, as it allows you to take advantage of parallel loading of assets. This is because a browser can only download a limited number of resources from a single domain at a time. Additionally, using a separate domain can make it easier to manage your assets and potentially offer more security, as you can limit access to just the sub-domain or domain hosting the static content.
Ultimately, both approaches have their advantages and disadvantages, so you should choose the one that best fits your specific needs.