I have 3 for my 550B.
I generally use one for 9x19mm, one for .45 Auto, and the third gets used for everything else - usually .380 Auto.
However... I still have some extra "change-over" time when going to .380 Auto, because I don't own a proper .380 cartridge conversion.
Instead, I use the .223/5.56 shell plate and 9x19mm powder funnel / expander. (I also use a .38 Special "Wadcutter Only" die for seating... but that's a different matter.
If I had more money lying around, I'd have a full quick-change kit (including powder measure) for each cartridge conversion... but I still haven't found a money tree.