Corrugated boxes and poly bags on their own may be enough to protect your shipment from the harsh handling realities of any courier, postal or shipping service available however to ensure piece of mind sometimes the use of void fill materials such as bubble, foam, paper or biodegradable peanuts is the only way to go.
The type of item your shipping can determine the need for void fill which helps secure the internals of any package at a reasonable cost. If an item is fragile or moves freely within the container then it will pay dividends to use void fill. Why? it reduces the chances of anything breaking, coming loose or revealing what’s inside the packaging for thieves to discover.
As a shipper you must decide what best suits your needs and your customers. If cushioning is your top priority then using bubbles or foam is more suitable at the cost of warehouse space. If your warehouse is limited in space then paper is the better choice but you might need to have it manually placed inside the package. If you want to venture in an environmental direction then using peanuts might fit. If choosing one of the others is difficult, use a combination.
There really is no wrong choice since customers will appreciate the level of care taken to ensure what they’ve ordered arrives on time with little to no damage to claim since you’ve chosen to use the proper void fill at that moment in time.