Should laminate flooring be the same thru the whole house ?

I think it looks nice but don't think it's the law!

Not necessarily. Before I ripped it out, I had it in my kitchen and bathrooms only. Carpet in rest of house. If you have the same flooring throughout, it can make a small area seem bigger.

that is your decision ...no other opinions are needed

It gives a certain flow and cohesion but it's not necessary.

Absolutely, yes it's a relatively inexpensive way to pull the whole house together giving one consistent look without spending a fortune or making it too matchy-matchy.

We have hardwood in the living room, dining room, hallway and both bedrooms on the main floor. The bedrooms are slightly lighter in color than the rest. The kitchen is 12x12 tile close to the hardwood color and the back room is wood look tile in close to the same color. All of this works pretty well together. I don't know if I would want laminate in the kitchen or the bathroom, there is too good of a chance for water spills and damage to the laminate. I want to use vinyl plank in the bathroom when we can get around to it.