Last week I wrote an article about my long distance relationship with my boyfriend. I can't post an article like that without posting an article to someone I miss just as much - my best friend Mary. But Mary's more than my best friend; she's my sister. Here's how to know if your best friend is your sister too.

1. You let yourself into each other's houses

You know their garage code and which door just always happens to be unlocked.

2. You go right to their fridge

You don't need an invitation, especially since you know where everything is. It's basically your house anyway.

3. You have multiple sleepovers a week

Even on school nights just so you can jam on the way to school (one time we didn't get to school till 1 PM sorry mom).

4. Referring to both your cars as "our car"

I specifically remember saying "Where'd we park our car?" multiple times.

5. It's always "we did this" and "we like this"

And everyone just knows she's the one you're talking about.

6. Your list of inside jokes is gigantic

When I went to college Mary gave me a four-page list of the jokes ONLY from our senior year (no exaggeration).

7. You miss them like family

1,000 miles has got nothing on us.

8. You love them unconditionally

Nothing will ever break you guys.

9. You're each other's biggest support system

Always.