Hey,
I don't own a warehouse myself nor am I a successful eBay businessman but just like to point out a few advantages and disadvantages about owning a warehouse:
Advantages:
- You can hold large amount of stock depending on the size of the warehouse
- Warehouses are easy to maintain for example, you select the product that wants to be shipped out, package it and hand it over to the courier
Disadvantages
- Rent is probably at a high number
- Insurance will probably cost you alot aswell
- Theft often happens in warehouses (depending on the security level)