I notice them when the leaves are damaged or old. Maybe the others can better chime in.

Sure. Thanks for your advice!

I would also not worry too much about the spots. The webs to me, anyway, look like regular spider webs like you may have a small spider living in your plant which would not hurt it. I feel that way because in one of your pictures it looks like small insects or pieces of medium stuck in the web. If you look closely maybe you can tell if there are small insects caught in the webs, it might just be a small spider. If you would feel better, you could still do the treatments for the spider mites anyway. Won't hurt anything. But by all means keep it away from other plants in case it is mites. I would go ahead and repot it in new medium.

Yes, it could just be a small spider web. I don't know a lot about spider mites or Dendrobiums so it's very difficult for me to know.
Yesterday I did treat it with some water and alcohol and I'm planning on doing it about twice a week for three to four weeks.
Someone on a different forum mentioned that the yellow spots could look like scale. Do you think so too? And do you agree with Dollythehun that I shouldn't worry about the black spots?

Thanks!

I see those yellow spots sometimes. They are usually nothing. I'll post a picture of mine later. They can get pretty gnarly looking and still be healthy. In the beginning I worried a lot too...

Oh, thanks. Would be nice with a picture of your plant to compare with my own.
So... basically, there might not be anything wrong with my plant like, at all?

Perhaps not. I'll post later. The older canes lose their leaves. If they are bruised or damaged they can get spots. The newest leaves are the only ones that look fresh and perfect, at least here.

Well, the leaf with the most black spotting on my plant is a leaf that's on a cane which isn't very long - so I'm assuming the cane isn't very old either. I actually don't know how that works.
Looking forward to your picture.

I cannot upload those pictures. I have shrunk them to no avail. Sorry. Well, and then here they are. Ah, technology:)

Haha, aw. It's a little hard to see what's on the pictures, but thanks for trying! :)