Your feathered friends spend most of their existence in a Cage, so picking the right cage for the Bird is a crucial decision. Investing in a good cage is something that you need to consider as the lesser cost cages are not only usually less attractive but also don't last as long.
A case choice is completely dependent upon the type of bird. If you have a bird that will be flittering and making use of its wings, a flight cage is the best selection. These are 'wing friendly' and will allow exercise as well as a sense of freedom.
Keeping your bird cage clean will be one of the best ways to keep your birds healthy. Choose a cage that offers a 'litter tray'. Easy removal and cleaning is recommended with a litter tray and doesn't require that you open the door.
Feeding and water dish access is another consideration. Some cages have the dishes attached to the door so that you can open them and place Food or water directly. Other cages offer outside access for more convenient food and water additions. Make sure that the food and water areas do not have small crevices where excess droppings and food can gather. This can harbor bacteria which in turn can cause illnesses for your birds.
Some cages now offer built-in shelves. This is an excellent location to store food. Inside 'shelving' that is designed for the birds themselves allow them to hop (or flitter) from shelf to shelf but is not designed for food storage.
While metal cages might be the cheapest and are rust-resistant, you might want to consider a powder-coated cage. These are available in a number of attractive colors and the powder-coating is heated to adhere to the metal. They are less prone to rusting and a lot more attractive. Stainless steel cages avoid the rust problem and are becoming very popular with bird owners. They are a bit higher in price but are well worth the investment.
Size is always a major concern. Larger birds will not thrive in a cage that is too small, although you can have smaller birds in larger cages and they do quite well.
Links for this article are from Hartz and Drs Foster & Smith.