Bubbles pop easily in many situations. The first situation is when they come in contact with oil and dirt. Our hands have oil and dirt on them! A soap bubble pops when it touches oil and dirt because a bubble is just a thin film of soap and water filled with air. The thin film can break when it touches oil or dirt, which our hands have on them.
Another way bubble can pop is when the water in them evaporates. Between the air and the soap film, there is water. As soon as the bubble is blown, depending on the environment, the water in it will start evaporating. The layer of the water is gone, so the soap film collapses and the bubble pops. You can add glycerin to bubble solutions to make the water evaporate slower. Glycerin hooks on to the water molecules, making them evaporate slower!
Many different variables can determine how long a bubble can last without popping: the air temperature, wind, ventilation, and even the type of water!