'up selling' is a dirty word when you sell someone they don't need, or will benefit from.
The vast majority of carpets clean up like new and that's after possibly years of abuse, so if they manage to survive that onslaught and clean up like new, why would the carpet, or the customer benefit from a protector? Surely logic says that those carpets are stain repellant int here own right, otherwise they wouldn't clean up like new.
Unlike the shoe shop scenario, we are trying to develop an ongoing relationship with our customers and hopefully that relationship will stretch many years into the future and that relationship has to be based upon one thing - trust. If you recommend a product, it has to be to the benefit of the customer and not just a grab for extra money. If you sell protector and it doesn't work, or do what the customer thinks, or believes it will do, they'll blame you and that vital bond of trust will be broken.
One way to get people to trust you is if they ask you about protector to say, 'no, your carpet doesn't need it.'That doesn't mean we don't sell protector, but we only sell it to customers who actually need it and they are very few.
Simon