In North Texas, we're built on red, clay soil. The soil expands and contracts as it dries up or gets wet. As the soils move, it moves the slab. Small, hairline cracks in the brick and mortar are not much cause to be alarmed. When the cracks become larger is when you have an issue. You'll also notice squiggly cracks at the corners of windows and doors. A big tell is when doors stop to latch when you close them.
Right now, we're on water restrictions. Most cities can only water on their trash days. I'm lucky, as my city has two trash days a week. The majority of the areas only have 1 trash day a week, which is only one watering day a week. Also, you cannot water between 10am and 6pm.
You are not restricted when it comes to soaker hoses and hand watering. Many people have blamed the restrictions for causing foundation problems, but for under $50, you can go to the store and buy soaker hoses to place around your entire house. Hoses should be about 18 inches from the slab as you don't want water to be trapped under the slab. This $50 or so could save you thousands!! There is no excuse to not water with soaker hoses.
Most cracks don't signal foundation problems. Some times a crack is just crack... at the speed some of these houses are put together, it's sometimes called bad workmanship!