About three years ago I opened the sofa bed in my spare bedroom (not used frequently) and realised the room was in the process of being eaten by what seemed like a million moths. From that point forward it has been a painful learning process as they spread around the house. Rugs, carpets, clothes, etc.
These moth traps have been part of my process. Placed in the right location and they are extremely effective. For example, one in my bedroom, under my bed, caught something like 40 moths last summer.
This year I am hoping the problem is behind me, but I will be combining these traps with spray, along with regularly checking danger areas regularly (shoes sat on the carpet in my wardrobe for example).
Moving back to these traps. They are simple to use and work well. If you are getting no moths on there it is probably the wrong location. Get the right location and you'll see how effective they are. I'm hoping this year is the last time I need them, but if the problem does continue I'd definitely get them again.