A HELOC's draw period often requires that homeowners merely pay interest payments; sometimes, flexible payment options are available. So, people can be lulled into a false sense of security about their ability to repay the loan. Although they must be qualified to borrow the money, a lot can happen to your finances in five to 10 years, potentially making that full payment wholly untenable, especially with larger-than-planned lines of credit.
HELOCs also tend to have variable interest rates (fixed-rate HELOCs are available, but not every bank offers them), further compounding the problem. So, before you agree to a HELOC, make sure you really understand what you'll be paying in 10 years, and be sure your financial house is in order.