It depends on the retreat. I've been to the ones at the stores, there you take your own machines and accessories. They also will sometimes ask that you bring your machine manual; especially if its a machine that they don't sell.
I've been to a couple of retreats at a hotel. Its all inclusive. They set up the classes differently both times even though it was the same company. The first time we rotated and got to take all of the classes. The second time I liked the most because we got to chose what we wanted. That was good for me because I was just getting back into garment sewing and my favorite teacher Angela Wolf was there and I took 2 of her classes and one purse making class. I love making purses because I like things that are different and I can't afford the unique ones from Coach any more. Even if I could, me making them gives me the most one of a kind that I like. Plus since I have the pattern I can hack it to make it look differently.
The one thing that I've learned, no matter what I take good scissors. Especially if its embroidery. They normally do have presentations. Ours were either before or after lunch. After 5 we were on our own. The 2nd retreat they offered things to do after 5, one of which was we could go back to our class room and at least the helper was there to help us complete our project. I loved going home with completed projects.
So yes, do ask questions. Make sure of what your going to make. I've been to a lot of them where the machines were included but we had to rotate meaning that with each project only one person was making something. So you would only have about one project or maybe two small ones per day. They did give us a cd with all of the projects on them. find out if the pattern is extra. The last one I went to instore, they had cut the fabric, it wasn't all cut the right size and then some of the fabric didn't come in so we had to wait a few weeks to get the rest of the fabric.