Software up to date
Out-of-date software can cause performance problems. In open apps, click on the application menu and select ‘Check for Updates’. Download and install them if there are any. Now, go to the App Store pane in System Preferences and check off ‘Automatically check for updates’, ‘Download newly available apps in the background’ and ‘Install app updates’. Also, click ‘Show Updates’. This passes you to the App Store app where you can download them.