Assess course potential: Some composites does want wider joist gaps while dense hardwoods may want wider joist gaps to prevent sagging.

https://www.scribd.com/document/971674353/Guide-for-the-New-Braunfels-Deck-Building-Company-Material-Selections-for-Long-Term-Value-180531

Assess the ability of the course: some composites require tighter distance to evade sagging while dense hardwoods may course wider joist gaps.