Have you ever heard the expression "Age is just a number"? It's really just something you say more and more as you get older. The truth is, age is just a number and it doesn't necessarily represent how old you are.

To know for sure if you're getting old, Guyism.com is telling you to just look for the following eight signs.

8. You routinely throw out your back.
7. You start doing your own taxes.
6. You prefer to stay in on a Saturday night.
5. You start watching the nightly news.
4. You go to sleep before midnight every night.
3. You keep plants in your house.
2. There is more food than alcohol in your fridge.
1. You have gray hair ... of course.