Which of the following is a key characteristic of wood shakes?

Wood shakes are indeed known for their high durability, which makes them a popular choice for roofing materials. This durability stems from the natural properties of wood and proper treatment during manufacturing. However, while they are durable, effective drainage is essential to maintain their longevity and prevent issues such as water pooling, mold growth, or wood deterioration over time. Proper installation, which includes ensuring that water can drain effectively off the roof, is crucial to avoid these potential problems.

The other options highlight misconceptions about wood shakes. For instance, they are not lightweight and do require some slope to function effectively, contrary to the claim that they need no slope. Furthermore, shakes are typically not uniform in size; they are often handcrafted and can vary greatly in thickness, length, and texture, which can contribute to aesthetic appeal but also results in variations that wouldn’t qualify them as uniform. Finally, while wood shakes can be used on a variety of roof slopes, their performance and installation techniques often depend on the specific slope of a roof, which makes the applicability on "any" slope incorrect. Therefore, understanding the need for good drainage paired with their durability best captures the essence of wood shakes.