Bifold metal door panels could be a great choice if you're sick of wooden or vinyl bi fold doors which break, and bend and warp. If you instead stick to metal and steel, then you won't have any issues with durability and strength. There are a couple of different styles available in the stores which feature folding metal doors which would be ideal for a closet space or other storage space where you need practical and stylish doors. These metal bifold doors for example by Dunbarton are really nice and feature wide louvers and fine trim mouldings.
Steel Bifold Doors
"The wide louvers and delicate trim moldings have made The Classic a favorite bifold door for many years. Limited Lifetime Warranty. Heavy-duty, long life bifold. Easily installed–only a screwdriver required! Patented Slimfold hat and hardware system pre-installed. Smooth and quiet operation. Breaks over center allowing maximum opening. Spring loaded guide rods for self-alignment"
These doors can be found at dunbarton.com
If you're unsure about what design would fit your space the best, then these doors are a great choice since they are so versatile. If you purchase a pair of steel bifold panel doors, then they should keep in nice condition for many years to come, however they can also add an elegant design element which blends in nicely. Most of these types of doors have a white finish, however you can surely find similar doors in black or other colors, if for some reason you find white a bit too bland. On the other hand, if you have simple closet doors, then you can put forth more effort towards style at other parts of the room. No matter what you prefer design wise, metal doors are practical and durable and would be a nice choice for any home.