I decided to pay our I-bond interest instead of holding and claiming all the interest for each bond when I cashed it.
Annoyingly, it's correct Treasury Direct only generates a 1099 for when you cash an I-bond.
But if you want to claim it yearly, you can start at any time, even when you have held the bonds more than 1 year, like us.
I made a spreadsheet where I listed each I-bond and the date purchased. Then I used the treasury calculator with a little trick so it works on electronic bonds.
The trick is: since the calculator is made for paper bonds, it only works up to a $5K value. So when I had a $10K bond, I just doubled the value I got for $5K.
It's important for me to track in the spreadsheet, as next year, the calculator will still show total accumulated interest per bond, and I'll have to subtract what I already claimed for each bond.
If one is smart, a person can look at their account on the first day of the new year, to see the total value of the bonds with accumulated interest for each one. No need to use the calculator.
When deferring you can switch to claim it all yearly anytime without notice. But to then go back to deferring the interest, a person has to fill out for IRS forms.
Now, when I cash in our I-bonds, I have to report per bond to the IRS how much interest I've already paid the tax upon. If I die and my heirs don't know, they will pay too much tax.