The really important aspect is to decide between a working Cocker and a Show Cocker, essentially like having two different breeds!
My Working Cocker...endless energy and bored very easily, could run 30 miles in a day, swims straight out to sea after seagulls, (a km once)
Loving and smart as can be, steals everything, thinks for himself when you call him back before he decides to come.
Would be very unhappy if not with a busy family and tons going on, athough we don't work him, we have a 2 acre garden and extended family often outside with him, needs a couple of off lead hour walks daily as a minimum.
Show cocker...longer coat bit more maintenance, same loving gentle temperament, but happy to curl up with you on your feet after an off lead run, intelligent and easy to train, but follows commands without considering his options first!
Happy to play endlessly, and much less prey drive.
Both energetic, clever, trainable and very gentle, good with other dogs, children and love people in general.
I would caution against a working cocker if you are a first time owner.