If your car is driving straight and the tires are wearing evenly the alignment is good or good enough. To check the alignment takes almost as much work to do the alignment because most of the work is putting on the equipment. Some cars even make the technician put a weight in the front seat to simulate the driver, so you're going to pay a shop nearly the same amount of money to just do an alignment. If there are no symptoms of a bad alignment, there really isn't a need to check it. The symptoms to look out for are the car pulling to one side or the other on the highway without input from the driver. e.g. you let go of the steering wheel and it starts drifting to the left consistently, if it pulls in a different direction every time, it could be the crown in the road. Uneven tire wear on one of the edges. e.g. your front driver's side tire's inside is worn, but the outside isn't. If the same tire has both the inside and outside worn but the middle is OK, it's a sign that you need to inflate your tires, if just the middle is worn, then you're overinflated, but if only one edge is worn, it's likely an alignment issue