Well, there’s really no short answer for the question. But, for many small businesses, the key consideration to outsource comes down to time. Not just whether they have the time to prep and ship customer orders out, but whether they can ship them in a timely manner consistently.
If you suddenly received a large influx of orders, does your business have the resources to produce, pack, and ship all the orders quickly enough to keep customers satisfied? Or does it make more sense to turn the entire process, and responsibility, over to a company that specializes in fulfillment?
The other issue is space. Does your business have the space available to stockpile quantities of your product(s) to satisfy customer demand? Or is that space better put to some other use? Only you can answer that.
Another consideration is consistent quality. Is your business able to consistently deliver the same reliable quality of finished product to customers? Or would a fulfillment specialist be better able to do that?