Worried about my cat

Question
Hi,

I have a white female cat who is approx 12-13 years old. She has always been healty and has always been a little overweight..nothing to be worried about though. Her belly just hung down a little. Lately I noticed she has gotten a little thinner, and she is also acting weird. I dont notice a drastic decrease in the amount of water in her bowl, so I cant say she is drinking excessively but she has been licking out of our cups. She will come up to my cup if it is on the floor and lick the ice cubes, she licks the outside of my boyfriends beer or soda can, and she also licks the bathroom faucet. I have never seen her do this and I am worried but I do not see any signs of her being sick. I just wanted to see if you had any ideas b4 I take her to the vet and get a hefty bill. Thanks!

Answer
Well it is really hard to say what is going on but her behavior would indicate that she is having some difficulty somewhere.
At her age, the most common thing cats get is kidney failure. It takes 80% of the kidney to go bad before it shows up so my guess is that she is on the cusp.

Your best move here would be to take her in and have some labs done to see what is going on. You could get her on some kidney diet to help if that is the problem. They can do well for a few years more sometimes if well monitored.
But you need to know and getting labs done is the only way you will.