My Cocker Spaniel had her tail docked but the owners did that when she was a puppy - we didn't have a say or anything. I personally wouldn't do it but equally Cockers look a little odd with long tails (you know, breed standards and everything). It just means that we get to call Willow, "stumpy" so that's the only bonus I can really think of. And it makes Willow look even dopey than she already is, being a lot shorter than most Cockers and having hardly any hair.. just adds to her appearance XD
I've never seen a dog with cropped ears so I have no idea about it.
In conclusion; I don't really mind, but if you did have to dock a dog, I would say that it's only really suitable for Spaniels, considering it's sort of breed standard. To each their own
As for neutering/spaying, I would say that it does have quite a lot of benefits. Though, equally, I do know a dog that got an infection because of it and was ill for a long time. She's better now, of course, but it's still quite scary. I would have spayed my two dogs, but both of them are quite old now and I don't think it would be fair on them to do it now. And with Willow, she runs non-stop and I'm afraid that we won't be able to keep her still and she'll end up pulling the stitches or getting herself into a worse state. If I could go back and spay them, I would, but because of so many varying factors, it just wasn't a good idea.
But because of this, we do take precautions when they're in heat to prevent any unwanted pregnancies.
There are a lot more benefits to spaying than cons, though, and I would say that it is a good idea. But obviously, if you don't have the money, the dog has some problems otherwise or the dog is really old, then I would argue against spaying/neutering.