Best practice for Windows involves not allowing anybody but the actual Administrator administrative access– everybody should be operating under a User or Power User account. One problem that arises from this is that users cannot change the time or view Windows’ built-in calendar from the Date/Time settings window.
To allow users/groups besides the Administrator to be able to change the time or view the calendar, as an Administrator go to Start > Run and type in gpedit.msc
When that comes up, navigate to Computer Configuration > Windows Settings > Security Settings > Local Policies > User Rights Assignment.
On the right panel, scroll down to Change the system time. Double click on it. Click on Add User or Group.
Here you can add the names of particular individuals you want to bestow this right upon, or you can simply enter Everyone and give that power to all users of the machine.