Honestly, seeing an old spice ad isn't going to make me buy old spice.

And seeing a 1 hour ad for some guy telling me to stop eating what I'm eating to have no-wipe bowel movements isn't going to make me buy the stuff.

There have been studies done about plumbers. The ones that pay money to get on top in the White Pages have worse reviews than the ones that work by word of mouth. I go by the same thing. If you feel that your product needs an ad, it's probably overpriced and / or doesn't do what it says it does.