This is an active dog who will need training if you want any hope of a quiet life! They are a joy to train however as they are intelligent and love working with their owner - but they will learn bad habits as quickly as good ones so reward-based training should start early and be ongoing.
This is a great breed for dog sports such as agility or even pet gundog work - and they will love having an active job to do. They will enjoy scent work games too.
It is important to train a Cocker Spaniel to enjoy handling and grooming (as they will need a lot of it) and to happily give up any prizes they may rather hold onto - always using positive, reward-based methods.
Given they have a working gundog background, they should be well socialised with cats (who they can learn to live with happily) but watched with caution around other small animals and birds.