My business does about 2000 orders per month from my Shopify site (and many more from Amazon's FBA), and I'm currently analyzing whether it would be good to take fulfillment in-house. My assumption is that it'd be a bad business decision due to the manpower requirements and warehouse space, but I want to be sure I'm considering all angles.
It's hard to determine how much it would affect me financially, as I wouldn't be paying a 3PL, but I'd have a bunch of additional costs. It would allow me to be a lot more nimble in terms of packaging and such.
I'd love to hear from people who transitioned.