Resistance bands are meant to be stretched and abused. That is how they help people get stronger, after all. But this type of action can have adverse effects on the material. The rubber will gradually get looser and easier to stretch. It might even break off if you pull particularly hard. This could be dangerous in certain kinds of exercises. For instance, you could fall onto the floor if hanging onto the bands while performing rows.
The best way to avoid these scenarios is to purchase a heavy duty resitance band. Beware of cheap products on the market. These might still provide a good workout but the longevity and quality will be questionable. The best bands are thick and made of high-grade rubber. They can take more abuse without showing signs of wear and tear. Check out the reviews from actual users for more information.