Combining a bunch of stuff into a single family (nesting) makes modeling more efficient, and can be less of a processing hit than groups – but there are some things to consider – specifically, if the nested elements should be SHARED.
By default, component families are not set to be shared. This setting is in the general parameters of each family.
A decision should be made UP FRONT on if the individual elements of a nested family need to be tagged/scheduled. If this is required, each nested family must be SHARED.
This is a modification you want to do sooner rather than later, as when the modified element is reloaded into the respective multi-element family, and then that parent family is loaded into the project, the other nested elements in the other multi-element families do NOT update automatically. This can result in differing appearance/behavior across what you THINK is the same element. Chaos ensues.