Shih Tzu puppy?

She is 5 months old and eats stuffs. I know shes teething but will it go away? Or shih tzu dogs stay eating things even in adulthood? My Sisters shih tzu is 6 years old and recently just ate their $500 beat headphones? Anyone raising a shih tzu? Someone with experience on that particular breed? Do they stop this destructive behaviour? If they do, at what age? Thank you in advanced.