In total, I have about 20 virtual hosts I take care of across a few workstations. On one system alone, I keep five running constantly, doing builds and network monitoring. At work, my Ubuntu workstation has two Windows VMs I use regularly. My home workstation has about eight: a mix of Fedora(s) and Windows.
A lot of my Windows use is pretty brief: doing test installs, doing web page compatibility checking, and using TeamViewer. Sometimes, a VM goes bonkers and you have to roll-back to a previous version of the VM; and sometimes VirtualBox’s snapshots are useful for that. On my home workstation, I have some hosts with about 18 snapshots and they are hard to scroll through they scroll to the right across the window How insightful. Chopping out a few snapshots in the middle of that pile is madness. Whatever Copy on Write (COW) de-duplication they end up doing takes ???fuhevvuh.??? It’s faster to compress all the snapshots into a new VM of one snapshot.