How do I keep my credit utilization low if I put all my spending on one rewards card?

The issue is that heavy spending on one card can spike that card's reported utilization even if you pay in full monthly, because the balance often reports on the statement date before you pay. A few fixes: make a mid-cycle payment (or two) so the balance is low when it reports, spread big purchases across more than one card to dilute per-card utilization, or ask for a higher limit so the same spending is a smaller percentage.

Remember utilization resets each month and has no memory, so a single high month won't permanently hurt you. But if you're about to apply for a mortgage or car loan, deliberately keep balances low in the cycle before you apply. You can still earn all your rewards, just pay early so the reported number stays under 10% to 30%. Model it at wealthserene.com/tools/utilization-optimizer.