Aquarium decorations?

I was told at my local pet shop that they usually last around 2 yrs. Taking into consideration whether or not its freshwater or saltwater. Saltwater is harder on them. Also if you add any medication to the tank that can cause paint to come off or get discolored. Also you have to use a soft brush on them so you don't rub or scratch the decor. Some fish are hard on decor too. I have noticed that in one of my tanks that has platies in it they pick constantly at the silk plants and some of them have gotten alittle frayed on the edges where my other tank has barbs in it and they don't pick at the plants all the time and those are fine. It's hard to say an amount of time but a couple years is a good guess.