Hi
See below KB links regarding Snapshots best practices and understand more about snapshots
VMware KB: Best practices for virtual machine snapshots in the VMware environment
VMware KB: Understanding virtual machine snapshots in VMware ESXi and ESX
As explained in the KB, snapshots are not backups.
Snapshots are not complete copies of the original vmdk disk files.
Taking a snapshot does not create a complete copy of the original vmdk disk file, rather it only copies the delta disks. The change log in the snapshot file combines with the original disk files to make up the current state of the virtual machine.
If the base disks are deleted, the snapshot files are useless.
Use no single snapshot for more than 24-72 hours.
You can just clone the VM if you need a backup of that VM, it would be better if you have a backup/data protection with VDP (vSphere Data Protection) or any other third party products for backup.
What vSphere licenses do you have?
If you have Essentials+ and above you can use VDP for free
VMware KB: vSphere Data Protection (VDP) FAQ
Q: Do I need additional licenses to use VDP 5.1?
VDP is included with vSphere Essentials Plus and higher.