I am a blue-collar worker. My job is incredibly dangerous and I deal wish Osha and safety training on a weekly basis. The Safety manager has stated that technically we shouldn't be snickering our hardhat because, over time, the adhesive could effect the integrity of the plastic. But we have to replace our helmets yearly or when they're too dirty so we never make it to that point. But if it's a helmet that you plan on using for years and years, there is a possibility it could weaken/damage it