The modern Inner Spring style mattress has been around for over 80 years. At the most basic, a traditional inner spring mattress uses a network of interconnected coils.
This mattress type is durable and relieves body pressure points. Plus, inner springs last for years and due to their manufacturing type, are a more cost-effective mattress as well.
However, inner spring mattresses also transfer a lot of motion from one side to the other of the bed. This means when your partner moves, you will move with them as the entire mattress shares a single spring system. This makes the inner spring a mattress that is not a good choice for couples or light sleepers.