This could result in over-commitment. The use of consumer credit is not always a matter of affordability, but rather a matter of priorities. You must decide whether the immediate gratification of buying something before you have the money is worth the extra cost of credit. Buying on credit now will delay reaching other goals in the future. The amount of debt a family can manage depends upon the amount and reliability of income and total financial obligations.
General rules are of limited value.
Some families cannot afford any monthly payments while others are able to make payments on several accounts. Suddenly the maximum advisable debt level has become the norm for safe debt level. While it is true that you may be able to make the installment payments without experiencing great sacrifice, such a practice is not sound financial planning. A better practice is to use the money saved by not using credit and apply it to financing future goals. This will help decrease the amount of time needed to accumulate the money to realize your goals.