Also if the trim is old enough to have lead paint, it also likely has some water damage

Costco carries it, as do quite a few online places

Absolutely you want to be paying that down towards the premium, but you also never want to miss a payment so I just wanted to make sure you weren't counting on those "91 days ahead" as a fall back option if you can't pay any month

If you borrow $10k at 10% and paid $1k/year, 100% of your payment would be going towards interest. That would be an interest only loan.

Because you don't want to pay this forever, you ask for a constant yearly payment which will eventually get rid of the loan. Now you pay ~$1,175, but since the interest cost ($1k/$1175=85%) stays the same, that means $175 is going towards principal. Next year, you only owe 10% interest on $10k-$175=$9,825*10%=$983. So this time, $1175-$983=$192 is going towards principal. And repeat for 20 years and then the loan is paid off. It goes to show how powerful compound interest is, both positively and negatively.

BTW, if you wanted the interest specific part of your payment to be 5.5% of the overall payment, you would need to pay ~$950 next month. Then the following month, about $850

>Am I essentially paying for expected full-term interest (if I were to make 0 additional payments above minimum monthly payment)?

You need to clarify this portion of your statement: "My monthly payments are "ahead of schedule" by 91 days."

Are you paying future months, or are you applying your extra payments towards principal?

Gold is newer than that, it wasn't formed as part of the big bang

Do you need wired internet throughout the house? Far easier to just install a mesh wifi network IMO