A useful starting point
Mass describes how much material is present by weight; volume describes the space it occupies. Equal volumes of different ingredients do not automatically have equal masses. Packing and preparation can also affect a volume measurement.
Keep it in your kitchen notes
Use the unit and method supplied by a reliable recipe. If converting, consult an ingredient-specific, appropriately documented conversion rather than applying one universal number. Keep the original quantity beside the converted value so you can see what changed. A scale can support a mass-based instruction, but using one does not make a guessed conversion correct.