Many product manufactures have wholesale distribution as an ongoing marketing plan and what support that is necessary comes down to warehouse space and adequate product shipping capabilities. Further, as might be required, Accounts Receivable and billing, EDI and other tendering round out the backend fulfillment.
Generally speaking, start ups and smaller manufactures tend to lean towards outsourcing due to lack of space and staff. And while drop shipping is a solution for many, inventory control and centralized full cycle fulfillment is served best from one location (high SKU counts from multiple product suppliers). And most brand sales management seeks a warehouse and distribution vendor close to the production vendor as possible. Logistics 101 in transportation and cost savings as it were.
And mixed carton LTL shipments are the norm for many sales, though not all 3PL services handle these crucial shipments to service retail outlets. Nor do many public warehousing companies which are great for high inventory storage as long as your fulfillment and distribution vendor is close. It’s normal for storage cost savings to use both a public warehouse from the same town as fulfillment vendor; especially if inventory is such that turnover is slower or say 6 months or more from time of receipt.
For guidance, 500 or more pallets that won’t turn over in say 12 months, best to think of public warehousing too—but look to the fulfillment vendor to coordinate for convenience. Usually, the fulfillment vendor can get the best price in the location depending on the product type.