I used it a few times and my shoulder stopped hurting right after using it. Then since I needed more testing I asked my parents to try it out and my mother said it worked great several times for both of her knees which hurt her pretty much daily. I can't speak really long term but it's been great for me usage we've given it.

Right, twice a day max 20 mins shouldn't be too much (10-15 might be more ideal, MAX 20). I'd never suggest anyone use it more than that. Before bed... might differ from one to another as some seem to think it has helped with relaxation and thus improved their sleep.

Red lights of any kind make me sleep great. Red light increases melatonin.

Not sure about sleep but my shoulder hurt really bad for more than a day then I used this and within hours it actually felt better which I hoped for but skeptical of but it helped!

Alligators? I'm not 100% sure but both the heat and infrared light aspects are something reptiles enjoy and benefit from as they absorb it through their skin.

I'd be concerned about shining it in their eyes, these lights are extremely bright, if you can keep it on their bodies, I guess it would be ok, I have a similar light to the one shown, who knows maybe the same brand, I bought it about 2 years ago, they also sell versions with 2 wavelengths of light, deep red like the one shown, and infrared (invisible), the IR, supposedly penetrates deeper, and the red works better for upper layers of the skin.

This one has red and Infrared and for sure you'd need to be careful using it around animals unless you can get them to wear UV goggles. 😂