Will you be traveling with you dog? If so, consider plastic dog crates that are lightweight, foldable and portable. Plastic dog crates can be easily stored and carried for air or road travel. Also, these dog crates provide extra insulation during cold weather and can serve as a dog bed.
On the other hand, if you prefer plenty of ventilation and visibility for your dog (especially if you are living in a hot and humid place) and want a crate that can be easily cleaned, you can go for wire or aluminum type dog crates. Some of these dog crates can be easily folded down into convenient sizes just like plastic dog crates. Nowadays, regardless of the type of dog crates, most of them can be assembled within minutes.