Designing for clients and storing templates

If you're a Circle member you can get trial websites for 6 months, and these can be extended. They can also be duplicated and this typically resets the trial. I don't know of a better way to keep custom templates. As a designer on Squarespace for many years, I haven't had much need myself to have my own templates, but I will sometimes duplicate a website I've created in the past to fulfil a similar need, though I generally like to start from scratch to build more unique designs.

(Memberships are per website not per account)