It’s safest not to assume that your cat has started meowing more because she has become more demanding. More vocalizing than usual means something’s wrong. It could be behavioral — fear, grief for the loss of another pet, even boredom — or it could be medical. Medical causes for an increase in vocalizations include anything from a respiratory infection to hearing loss (which may be expressed by yowling rather than meowing). Persistent vocalizations that hadn’t been going on previously could also be an indication of pain.
If your cat is “talking” more, be glad she is able to communicate that all is not what it should be. It gives you a leg up in sussing out that there’s a problem, which in turn allows you to take action.