All the image and video licenses on Vecteezy are available for use perpetually. That means you can use the images and clips forever, within a single project.
If you would like to use that same image or video clip again in a new project, you must download it again to re-license it for your new project.
You may not download and stockpile content for future use. You may save files on your computer for a duration of 30 days while your project is in development. Once your project is complete, all unused images and video clips must be deleted from your computer or other storage devices.