Hypothetical: I determine that all my personal belongings in my condo are worth $10,000 total, and I buy $20,000 worth of coverage. Two years later everything is completely destroyed by some accident. Will I be paid the whole $20,000 by the insurance company (which essentially gives me a $10,000 profit)?

No, you have to prove your losses, draw up a list, use your inventory, etc.

I’ve never seen an "agreed amount" clause on contents. It’s the LESSER of, the value of your stuff, or the policy limit.

It makes the inventory part pretty important.

BUT, the average person has more than $!0,000 of stuff, also.