Thinking back to my old film days, I have switched brands several times. I started with Pentax then went to Nikon. From Nikon I went medium format to Mamiya. From Mamiya I went back to Nikon.
Then came the digital age. I went from Sony to Nikon to Olympus to Panasonic to Nikon and now to Canon!
I currently still have most of my cameras (except for the Olympus) and lenses. Batteries are the biggest challenge for me. Whenever I get the urge to use one of my old digital cameras I find that the batteries need to get replaced (especially with my Nikon DSLRs).
My reason for so many switches in the past was because I needed something specific from a particular brand/format at the time. Because I have kept most of my equipment, I really never fully committed to truly switching over100% to one brand or another. I currently use a Canon T3i with three kit lenses for travel because it is a decent, lightweight set up. My older Nikon bodies are too heavy/cumbersome for travel. I use Nikon whenever I need to use a longer lens or for sports events.
How many times have you switched? What were your reasons? Any regrets?