Should I build in my agency account or in my client's sub-account?

Build templates and anything you want to reuse in your agency (master) account. Think of it as the parent account with your sub-accounts below it. Build agents, forms and other items there, put them in a snapshot and pass them down to your sub-accounts, the same way you push updates. This is the easiest way to maintain many clients. Snapshots only go down from the agency account to sub-accounts, never up.

If one agency account serves several niches or industries, still build everything in the agency account and stay organized with folders. There are folders for agents, forms, phone numbers and more, so keep them organized by niche.

If you are building something for one specific client that is not a template, such as that client's own website, build it in the client's sub-account. You can always work inside a client's account by logging in as that client.