Now, I run a bunch of lxd containers for development, and they are a bit more ephemeral and might get re-setup more frequently. This allows me to avoid having a base system with dependencies for stuff I don't really need.
I sometimes also reformat when I introduce new disks or replace them with bigger ones.
I would only reformat again if changing to a different file system. Eg: XFS to EXT4
Even that is not really necessary, since fstransform can convert file systems in situ.