Despite repeatedly pleading with my kids (followed by warnings and the occasion threat), I rarely get my iPhone or iPad back from them in the same state as I lent it out. They change the wallpaper, rearrange app icons and folders, and generally mess with my settings each time they are allowed "screen time."
My kids ask to use my MacBook Pro less frequently, but when they do, they have their own user accounts so they can select a new wallpaper image as it strikes their fancy while also being restricted from certain corners of the Web. If you have a Mac at home that's shared among family members, I suggest you take a couple of minutes to create multiple user accounts.
Adding accounts
To get started, open System Preferences and select Users & Groups. Next, click the lock icon and enter your password in order to make changes.
Administrator: can add and manage other users, install apps, and change settings. The first account you created when you set up your Mac for the first time is the administrator. You can have multiple administrator accounts and can always make another type of user an administrator after the fact by checking the box labeled "Allow user to administer this computer" on a user's profile.
Managed with Parental Controls: can access only the apps and content specified by the administrator managing the user. The administrator can restrict the user's contacts and website access, and place time limits on computer use.
Sharing Only: can access shared files remotely, but can't log in to or change settings on the computer.
You'll likely use the Standard account for the other responsible adults in your household and use the Managed account for your kids. For each user, you can give it a name, a profile pic, and either a separate password or your iCloud password.
You can also set up a group and add a subset of your users to it, but it is really only useful if you closely manage your shared folders. (A group can save you a couple of clicks when setting up access rights to shared folders.)
Parental controls
For Managed users, the parental controls let you restrict access to a variety of content, including certain apps and Websites, and you can also set time limits.On the Apps tab, you can enable Simple Finder, which lets you limit the items in the Dock to a three folders: My Applications, Documents, and Shared. You can then check off which items you'd like to appear in each. Also on the App tab, you can check a box for Limit Applications, which lets you to set an age rating for apps the user can install (up to 9+ or 12+, for example).
On the People tab, you can set up GameCenter restrictions. You can also limit whom you child can contact with the Mail and Messages apps.
On the Time Limits tab, you can set a limit on the number of hours your child can use your Mac on weekdays and weekends. Likewise, you can set a bedtime range during which your Mac is inaccessible.
Switching between users
You don't need to log out from one account in order to log into another; multiple users can be logged in at the same time. To change from one account to another, click on your user name in the menu bar and select another user from the drop-down menu.
