For Salomon Speedcross 6 shoes, it is generally recommended to choose the size that corresponds to your usual foot size. Here are some key points to consider:

- Speedcross 6s are designed with Sensifit™ technology, which offers a precise and optimal foot hold, meaning they should feel comfortable and snug without requiring a size up.
- It's important to check the sizing charts provided by Salomon to ensure you choose the right size based on your foot measurements.

In summary, you should order the size that matches your usual foot measurement, without needing to size up unless you have specific personal preferences for comfort.