I keep hearing that you should only spend up to 20% - 30% of your credit card limit. Furthermore, owning multiple credit cards is not bad as long as you can keep it under the aggregated 20%. But, it is also said that no credit card rating is also terrible and that not using your credit card will lower your score.
Couple of things to consider.
- Building credit with a FICO score is based upon your debt utilization, Payment history, and income/debt ratios. Research FICO scores and it will tell you how they are calculated.
- If you have zero credit, don't pay interest to build credit. Make planned expenses when you have the money in the bank to cover purchases. Research other items that also build credit like transaction histories such as with utility companies or wireless phone providers.