There are several default settings you can set on a per section basis when creating new pages / galleries (example: the section your Client Galleries are in). To edit these settings, click edit under the section name in the let menu of the site content area.
Default Expire & Private Page Settings
Here you can set the default for when creating a new page / gallery, how many days until it expires. Also the option to show / hide pages that have expired.
Also there is the option to set the default when creating pages / galleries, if it is going to be password protected or not.
Set the option to have watermarking automatically enabled when uploading photos.
Default Price List
If you have multiple price lists, you can select the default one to use when creating galleries in the section.
Default Page Status
Here you can set the default page status to Published when creating new pages / galleries.
If you have creating different shipping groups in Settings -> Shipping, you can select the default one to use when creating new galleries in this section.
There is a tab across the top for Photo Defaults. These are the default photo display settings when creating a new page / gallery. Here you can also enable / disable social sharing of photos, search and more.
Also, if you make a change to the photo defaults, you can update all pages / galleries in that section with the new default settings.