I am going to install 4 LED downlights on a 3-way switch. My plan is to do panel-switch-switch-lights... similar to this image
I will be using THHN inside conduit from panel to first switch, and from first switch to second switch. My question is do I need to splice the neutral in the first switch box, or can I just make it a continuous run from panel - through first switch box - spliced to NM-B in second switch box?
Alternatively, is it good practice to splice here (provides future capability) or bad practice (unnecessary point of failure)?