Most DSLR's these days come with USER modes which are usually placed on the dial that lets you select Aperture Priority, Shutter Priority, Bulb, Manual. Some cameras come with USER1, USER2, USER3 or U1, U2, U3(Nikon), C1, C2, C3(Canon). You select one of these modes enter the camera parameters of your choice and the camera saves these parameters so next time you use the camera you don't have to enter them again. Some people swear by them like Ken Rockwell who is always talking about User Modes when reviewing gear. Most cameras offer 1 or 2 User modes. Some higher end cameras offer 3 User modes. The Pentax K1 offers a whopping 4 User modes. I don't know too much about User modes because I never use them. To me remembering Shutter speed, ISO, Aperture is enough. Maybe if I'm shooting Flash then Guide numbers and flash-to-subject-distance comes in handy. I don't think I can remember what parameters I stored in U1, U2, or U3 unless I wrote them down somewhere ? I once changed the back AE-L button to Auto Focus on my Canon EOS-3, because the shutter was too sensitive. Once in a while I might add a couple of Special-Functions, but usually I try to avoid this. Maybe if I was a professional, or I shot the same type of pictures over and over again, the User Modes might come in handy, but to me 1 or 2 User Modes would be enough. Once in a while I shoot weddings, no more than 10 a year. Even then, every wedding is different. The lighting is different, the people are different, the setting is different. I would need 10-20 User settings just to keep up. "Today I will use U3 for this wedding !" This just does not work for me. I once owned a Canon 7D. The camera had a reputation for being very customizable. The operating manual was 3 time as thick as your average operating manual, because of the extensive instructions on how to customize that camera. I said to myself the next rainy day I will sit down and read the entire manual, which I never did. Maybe I was missed out on something, but I'll never find out because I trade it in for another camera that did not hog the battery so much. No pun intended for those people who like User modes I would just like to know how and why you use them and if there is any benefit in using them.