Originally Posted by
serpens
Are balances reported only at the statement date?
For most cards, yes.
Originally Posted by
serpens
When does the balance on a particular card divided by the credit limit on that particular card have an effect?
After the Statement Date when the balance is reported to the CRAs.
Originally Posted by
serpens
Is it worth (or even effective) paying in advance of the statement date to reduce this ratio?
If you have utilization problems, it's worth it. I don't do it, but for some with few or only 1 credit card, it could be a good strategy.