According to the "low-cost hypothesis" (LCH), attitudes explain behavior only if complying with personal convictions requires little effort. Environmental research has seized this argument to explain moderate participation in pro-environmental action against a backdrop of rising environmental awareness. However, evidence for the LCH remains ambiguous, and recent studies have reported contradictory results. Here, we reconcile prior findings on household waste recycling and argue that many environmental behaviors evolved into every day, "normal" practices increasingly encouraged by social norms, and thus slip out of the LCH's scope. We combine a natural experiment exploiting households' variation in geocoded walking distances to drop-off recycling sites in Munich, Germany (N = 754) with an independent online survey (N = 640) measuring local intensities of recycling norms for two distinct waste categories, plastics and glass. Our results suggest that normative change narrows the LCH's scope to include only environmental action for which normative expectations are weak.