Having a second camera may sound like a bit of a luxury, but it's essential for working pros who not only need a backup camera in case one fails on an important photoshoot, but also to allow you to switch between two different lenses easily without having to spend time faffing around in your camera bag. This goes for any photographer making a living from things such as big occasions, sporting events and weddings.
So having two cameras is the important first step, a little secret tip is I also have my old DSLR in my car as a third backup too, just in case things go really pear-shaped! When choosing two cameras they don’t have to be identical models, though you may prefer them to be if you're after consistency between the files. It’s more important that they’re the same sensor size, such as APS-C or full-frame, and also from the same camera brand so that you can interchange the lenses easily. I currently use a Canon EOS R5 and Canon EOS R6 Mark II for my weddings, as this allows me to change cameras when I need the larger 45MP files from the EOS R5, or the lower megapixels and better noise handling of the 24.2MP R6 Mark II for low light situations.
