When leading a pitch I will sometimes switch from twin to half, but never back. Here's why.
First, some definitions, assuming you're climbing with two ropes that are certified as both twin and half:
Twin ropes: clip both ropes through each piece of protection.
Half ropes: clip a single rope through a piece of protection.
Normally when climbing using a ...
If a rope is certified both as twin and half rope, it is allowed to clip either a single strand or two strands.
If you alternate your clipping style within one pitch, you might be facing more rope drag than necessary and not used often. However, there is one notable exception. Most belay devices (tube!) are very sensitive to having your brake hand ...