Often companies do not list the fixes in a new firmware, it is a pretty sad thing many have adopted.
But at least with viofo it is safe to do as the new firmware have often been tested by testers before it is released, so very small chance of a new firmware ruining a camera.
In general the biggest danger are downloading a firmware for another model and trying to update with that, which are a option with for instance viofo having many models with sort of similar names.
But as long as you are aware of what model you have you should be able to find the correct firmware at the brands home page,,,,, or in here in the correct sub forum.
You can go by " if it aint broke, no need to fix it" but that way you can miss out on for instance image improvements that might have been made, but most often the firmware's are fixes in regard to functionality - new features and most often lastly image improvements.
Street Guardian always have a "whats new" doku with their firmwares listing what change / have been fixed.