The specific option you choose for aluminum sign thickness depends on how you plan to use the sign, and for how long. Thinner signs work great for business signs, property signs, directional signs, and other things because they are durable and resistant to corrosion. They are also very lightweight, making them a great choice for displaying anywhere that you need signage.
If you plan to use a sign for more than about three years, consider the thicker aluminum signs. The solid core makes these strong and more durable so you won’t need to worry about damage over time. When properly installed, a 0.125 aluminum ACM sign can last for several decades.