To clean the sofa without damaging the fabric
Yes, you do need shampoo. When hair is at its dirtiest, it will contain dust, dirt, skin flakes, salt and oil. A shampoo has to break it down and pull it away from the hair. Water won't do this alone so, shampoo to the rescue.
no, you need a special shampoo to kill lice.
Good Quality Shampoo=GQS
If shampoo if applied and rinsed without being lathered the shampoo will not have a reaction due to friction. This will cause the shampoo to be nearly pointless. The friction is what makes it "sudsy".
Shampoo and water.
no
no
No
Yes, or a shampoo license, which is like an apprentice license
yes you can i did it once big container i need my shampoo
no you should shampoo once a week and condition every day
Unless the dog has fleas and you need a shampoo that'll kill them, human shampoo should work just fine on your dog.