You wrapped up a big commercial project in Metro Detroit on time and sent the invoice the same day. The customer pays on long terms, payroll is due Friday and the next job starts Monday with money that is not in the account yet.
Invoice factoring turns that approved invoice into cash now. A factoring company advances most of the invoice once it is verified, collects from your customer on their normal terms and sends you the rest, minus its fee, when they pay.
Payroll goes out on time and the next job starts without you borrowing against your house. You factor only the slow-paying accounts that need it, keep the rest in house and stop turning down good customers because of their payment terms.