<human>: How do they work?
I have received 1 $50 face value US EE Savings Bond each year (purchased in the 11th month of each year) since 1990.

I know some of these bonds have interest rates close to 4.0% and others are as low as 0.63%. 

I have some student loans I'm paying off and was wondering if I should sell the low interest savings bonds (less than 1%) to pay off the 6.8% student loan debt. What taxes will I encounter? Can I avoid them? I'm 23 y/o if it matters.

Also I think all the bonds are variable interest rates (can be changed twice yearly) Why are some years sitting high and others really low? is there a max or min that these rates can go to? Is there a chance these 0.68% rates might rise in the future making it worth holding onto them?

These bonds earn interest for 30 years right? so 4% returns is pretty great for guaranteed interest. But I'm worried that they might dip lower (again this variable interest rate)

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: I don't know /r/Alot about these bonds I have even though I have over $1,000 in value in them. Help me please?