I only ever hand expressed, but I wasn't having to express more than once or twice a day. The pump just made my nipples sore. I did get cramp in my hand sometimes - 10 mins sounds good to me - would have thought is more about the amounts then length of time. Maybe you could try some different pumps out by hiring them (ABA and some pharmacies do it). Is great though that you can hand express - is a valuable skill if you ask me (means you don't always have to have a pump with you) and so many people never master hand expressing.