量力而行 Living Within Your Means

It is never a disgrace to say, "I can not afford it." It is shameful to commit yourself to expenditure you know you can not really afford and should not make just because someone else urges you to go against your own better judgment. I have respect for the person for who can say without any self-consciousness at all, simply and cheerfully, 'I can not afford it.' But I hate to hear a long-drawn-out explanation of why. As a matter of fact, we should never demand to know why a person can not spend money on something he says he can not afford unless there is s sound reason for his finding some way to afford it. Then you may, if you feel you should, try to show him that way, quietly and without irritating him.