One of the attractions of a 500 mm lens is the ability to pick out a detail from a distance. The first is a feeder on a neighbor's deck. The second is behind my other neighbor's house, separating his yard from the Tango. Finally, all roads lead to a soccer ball.
The longest lens I have is 200mm. I can definitely see that subject separation at 500mm. Side note: These photos make my want to shoot in snow, but I live in Florida.
When that's all I had, I thought 200 mm was a long lens. That was a while ago. I'd get something longer (1,000 mm) if I could afford it. ;-) Really difficult to use handheld, though.
We had the opportunity to live in Altamonte Springs back in the '90s near my brother's and sister's families, but my wife vetoed the idea. She said the humidity would mess up her hair. Also, hurricanes.
I use a sigma 70/300mm most often and like it. My pentax 200mm is amazing but really heavy. Sometimes i use a doubler on the 200mm but find it awkward. I have been thinking of something longer range but weight is an issue for me. Is your 500mm heavy?
My 500 is a Nikon catadioptric, which is not heavy at all, but it comes with other issues. It is a manual focus lens and with a fixed f/8 aperture. The bokeh is at best controversial and there is very little to be done about that other than pointing the camera somewhere else. You really need a high shutter speed; I have my D810 set for a minimum shutter speed of 1/500 second and let the ISO float, a little digital noise being preferable to unintentional motion blur. And the depth of field is nonexistent. Still, as I have less mobility than a few years ago, it lets me shoot without having to move around on uncertain footing.
P.S. A regular 500 mm FX format lens is considerably heavier and more of an issue to handle. All the handling problems of my catadioptric lens, excluding the bokeh, would still be there. A good tripod is a practical necessity.
My 18-200mm lens by tamron is very light because it fits my aps-c camera. It is only about the size of canon's f1.4 prime. Carrying heavy lenses is not something I have done yet, but I doubt I would mind the weight.
If you do go heavy, i recommend a tripod mount for the lens. Mskes a big difference. :)
I've considered renting a larger lens for street photography so that I get a better understanding for what its like to use one.