The first question you should ask yourself is whether the frame itself shows signs of corrosion. Damage to the structural support may cause the deck to collapse. Sometimes, corrosion will be obvious, as in cases where you can see the rotting on the edge of the deck frame itself. But you may need to hire a professional to do an inspection if you are not an expert in cabinetmaking. They will look at more technical aspects, such as railings and stair connections.
Fortunately, terraces with intact structural support, but worn planks and railings can get away with simply repairing the materials of the deck. You simply need to replace the individual panels and railings to be repaired. Some bridges may require a simple finish.
However, if you want newer materials, be aware that they might be heavier. In such cases, the bridge will need additional supports. The cost of extra help might be enough to install a new deck of cards.
In addition, old bridges prior to 2004 often contained chromated copper arsenate, a toxic chemical, a type of preservative for lumber labeled as carcinogenic because of the arsenic it contains. Fortunately, you can have these types of bridges restored by a professional, which can seal the chemical.