Years ago, you would see iron fencing all over the place. Its use was especially common on big estates and in public parks. Today, most metal fencing is actually made from aluminum, even if it has been painted black to look like wrought iron. Aluminum is a lot lighter than iron, it does not rust, and it's easier to install. In the average backyard, aluminum fencing is certainly a suitable choice. With so many choices, iron fencing is far from obsolete! There is still very much a place for it — and that place may be on your property if you fall into any of the following categories.
You need a fence that will withstand high impacts.
As versatile as aluminum is, it is not very resistant to impact. You could tap on it with a hammer, and it would bend. Iron, on the other hand, is very resistant to impact. You could drive into it with a car, and the car would have more damage with the fence! If your fence is likely to have a tree limb fall on it, a car crash into it, or a lawnmower bump into it, then you might want to go with iron. The fence will last several decades, if not a lifetime, and you won't have to pound out dents or have distorted pieces replaced.
You need a fence that looks really authentic.
Aluminum fences look similar to iron fences, but you can definitely tell the difference once you get close. If you have a historic property and achieving a certain look is your priority, then iron is the prime choice. It will develop a little rust as it ages, but that's part of the authenticity. You can also often find iron fences in more classic, historic styles, such as with pointed spires, since iron fences are often made to look old and this is not always true of aluminum fences.
You need a fence people can't destroy or breach.
One problem with aluminum fencing is that anyone with a sharp saw can cut through it. Thus, while an aluminum fence might look secure, it's not as secure as it looks when a criminal is insistent. Iron, on the other hand, would be virtually impossible for someone to cut through. Put pointy spires or some barbed wire along the top, and you have a fence that will keep intruders away in almost all scenarios.
Wrought iron fencing is not as common as it once was, but it is still a top contender in the circumstances above.