How does revolving credit work?
A revolving line of credit does exactly what it sounds like it does -- it revolves. When you pay off part of that credit line, it becomes available to use again as you wish, with a cap on the maximum amount of money you can borrow at any given time.
For example, if you have a credit card with a $5,000 credit line, you can go out and charge a new bicycle that's $2,500 and still have $2,500 to use if you need to, say, for a bike rack or some cool new gear. Although you shouldn't often charge so much on a revolving credit line at once, this is exactly what it's for -- covering large purchases over an extended period.
Alternatively, you can also use a revolving credit line to cover funding gaps for your business. So, if you have a business credit line that revolves, you can tap it during seasonal lulls to help cover things like supplies when cash flow is low. Again, the goal (in a perfect world) is to keep the credit balance to less than 30% of the credit line.