Can you reverse the sprockets on a cassette to lengthen its lifespan? I know my bike's rear cassette needs replacing, but before I do that, is it feasible to dismantle the 8 sprockets to reverse their spin? Can you increase the lifespan of a cassette by letting the cogs wear and tear the other way?
Assuming you have Shimano-compatiple Hyperglide cogs: No, you can't.
The cassette body is not symmetric, the cassette fits in only one position.
You could resort to adapt the cogs with a file, though. But shifting will be problematic at least, the cogs have certain indents to make shifting smoother.