Are they breaking off or falling out? Whiskers are just like the rest of the fur on their body... they will grow and fall out and grow back again.

If you're seeing an increase in whiskers falling out, or hair falling out in general, there may be an issue.

If the whiskers are breaking off (as in, the whisker is still in the follicle but is breaking off further down the shaft) I would wonder if the cat isn't engaging in an activity or getting into an area that is making this happen.

If you're seeing generalized hair loss, please consider a vet visit.