How long would 3g cart last me?

In my city I pay like $65-80 for a 1g cart and after getting tired of it I started looking at OK weed and found out there are 3g carts?? i’m a frequent smoker so a 1g usually lasts 6 or 7 days and .5g usually lasts like 3 or 4 days. I was surprised when I found out 2g exist. This is insane