Let's talk business for a minute...
I think as artists, we’ve all been there. 
Someone asks us to make 20 (or 200) of a thing… and the money is tempting. 
At some point, I think most all artists wade into the waters of making things in bulk or wholesale.
There are certain crafts that lend themselves to producing in bulk, and are a natural “fit.” 
Even jewelry sort of lends itself to being made in larger lots… things like band rings where you can put a different stone or design on each one.  However, it doesn’t work for everyone.

There are several factors at play here. Being able to purchase supplies in enough of a bulk so that you can bring the individual costs down. Being able to then produce the items in enough of a quantity to be able to offer them at half or less the cost that you would normally sell the item for… and of course, the time and energy to make the same/ mostly the same item over and over again. For some folks it is great. You get into a rhythm…. You knock out several at a time…. You become a sort of manufacturing “machine.” It takes a very special personality to be able to do that, and to have it work for them…. And kudos to those who do and can. But that is not me. And it’s not for lack of trying. I’ve been there. I’ve done 100 pairs of earrings in a week for a specific event.
I’ve made 50 rosary rings at a pop for gift giving, and I used to sell my envelopes at wholesale to a shop in Australia for several years. (which was cool).
It comes down to what you truly want to do. Do you have a plan for your business? Are you looking to sell a specific “line” of items that would lend themselves to more mass producing? Do you have several places that you market your items that would each want a sampling or variety of your work? Are you looking to sell your things in large quantities to shops and centers? Then this is a great plan for you. And it’s a great way to get your work out there.
As a dirt-poor artist (and I am not saying this lightly)… there is no way I could do this even if I was inclined. I just don’t have the funds to start up a production of items like that. And I am not willing to garner debt in order to start. It’s just my personal choice, there…. But one I feel strongly about. My whole aesthetic, has been one of re-use, re-purpose, and recycle. And that core belief is in everything I make, including my jewelry. I use recycled materials when I can. I salvage old pieces and fix them, or use them in new ways into new pieces. I buy metal, but I try to source recycled materials there as well. A couple years ago I made a decision to only use my handmade materials as much as possible. That means that most of my findings… are ones I’ve made. Yes, I am using up things I currently have (and yes, I have quite the stash)… but it’s the intention here that is important to me. I would much rather make pieces with great care, attention to detail, and have there be only one of them…. Than to mass produce them. I think there is a percentage of the population that would prefer to wear unique one-of-a-kind pieces, than something that perhaps 50 or 5000 other people might have.
There has been a movement sweeping the world for the past decade or so, to go back to simpler times. To embrace the handcrafted.
To respect the artistry that it takes for someone to develop the skills and the wherewithal to create something from scratch.

Conversely, there is a strong movement to make things en mass. To wholesale. To become (albeit on a smaller scale) a manufacturer of quality goods. And either is fine. Either is correct. It’s just a matter of what works better for you.  There is no “right” way to run your business. There is no set and firm answer that will work for everyone. Choose for yourself. That is the beauty of it all.