I dont know about Jo Von but I would think it would be the same everywhere. Sometimes people take engagement photos for a specific use (in newspaper announcement etc) but most people I know end up using their engagement sitting as a way to get comfortable with their photographer and being in front of a camera for formal shots prior to the big day...and of course you end up with some nice pics in the process. Just like a wedding, I think your engagement pics should reflect your personal style. If your dogs are your babies, by all means get them in the pics (of course this I would call in advance and check that the photog is OK with it). I have seen some very formal pics or casual in jeans or everyday wear. Our photog even had some pics of a couple who spray painted themselves gold and had sprigs in their hair in a very artistic shot (I cant see my guy ever doing THAT but I had to admire their creativity). I think the time varies by photographer but definitely try to do it, I think its worth it for the sake of getting comfortable in front of the camera.