Value.
I pay the extra for additional quality where it is warranted/justified/represents value. Spending more for the sake of it is foolish, just as much as spending too little and expecting too much is.
Some people think I am nuts for owning a £250 pair of sunglasses. They are still going strong for over 3 years, do not have a single scratch in the lenses, have not broken, fallen apart and work flawlessly. That is value to me, something I use almost every day and can rely on.
Same with my headphones for home use. Same with anything I will use and requires that extra bit of fit and finish.
I'm not a brand whore however, I loathe spending obnoxious amounts on, for example, clothing as to me a brand name does not represent additional quality. If it has a badge and I went out of my way to own it, it's more than likely the brand earned it's praise.