Hello
Consider some main aspects of Snapshot Generation:
1. Old-Aged Snapshots are not useful, because they are old enough that most of times you don't need them anymore. Many of Monitoring systems (also vRealize Operation Manager) recognized them as not-useful object if they are very old, and then warned you to remove them.
2. Many nested Snapshots can cause complexity in VM management, because each snapshot is depended to its previous snapshot. Too many snapshot in one path may slow down VM operation and you will need to consolidation action after a duration. Also elapsed time of consolidation depends on snapshot hierarchy and their dependencies. So avoid to generated depended (nested) snapshot.
3. Do not include VM's memory to the snapshot if you really don't need it. In other words create snapshot in power-off state or uncheck this option whenever you don't really need it. It will generate a VMSN file include content of virtual machine memory, big as Virtual Memory size, So you will require more space on your datastore for each snapshot like this.
4. For each reason if you lose one of delta.vmdk of your VM suddenly , it may lead to VM corruption, So you need to protect the VMs and their Snapshots more than ever.
I Wrote a post about Snapshot two weeks ago, I hope it can be helpful for you:
Virtual Machine Snapshot Details Investigation - Part 1