Well, just from simple physics alone, assuming the hubs and rims are similar, a wheel with fewer spokes will not be as strong and will not last as long as one with more. The question is how much less. Sure, there are 36-spoke wheels that have lasted decades. But will the 24-spoke wheel last 67% as long? Or 50%? Or 25%? All those may be the correct answer. It would suck to find out in the middle of nowhere on a tour. Bring spare spokes, and know how to replace them on that wheel and true on the side of the road before embarking on this journey.