I recommend On-Demand pricing 'until it hurts'[0], but that's because a ton of people I talk to are spending <$50/month on DynamoDB. At that point, it really doesn't make sense to spend hours of time optimizing your DynamoDB bill.
If you are at the point where you are spending over thousands of dollars a month on DynamoDB, then it does make sense to review your usage, fine-tune your capacity, set up auto-scaling, buy reserved capacity, etc. But don't waste your time doing that to save $14 a month. There are better things to do.
But it's really nice to have a database where you can set up pay-per-use, don't have to think about exhausting your resources, and have an option to back out into a cheaper billing mode if it does get expensive.
[0] - Hat tip to Jared Short for this advice & phrase
If you are at the point where you are spending over thousands of dollars a month on DynamoDB, then it does make sense to review your usage, fine-tune your capacity, set up auto-scaling, buy reserved capacity, etc. But don't waste your time doing that to save $14 a month. There are better things to do.
But it's really nice to have a database where you can set up pay-per-use, don't have to think about exhausting your resources, and have an option to back out into a cheaper billing mode if it does get expensive.
[0] - Hat tip to Jared Short for this advice & phrase