The clock that appears on the right side of your menubar can be customized to suit your needs. You can choose what to display and even switch to a compact analog clock. In System Preferences, you can set the time to be spoken aloud at regular intervals. There are many third-party apps in the App Store that offer even more options.
It is a good idea to have the time announced to remind yourself to look away from your computer to rest your eyes and stand up and stretch.