Making a commitment doesn't mean the same thing to everybody. I'm not talking about making a commitment to lose weight, or handle finances better, or any other commitment you make to yourself to make your life or health better, but commitments made to others for their benefit.
To me, making a commitment to someone for something they need means I promise to be there for them, help them, or do what I said I would when I said I would. It doesn't mean I'll do what I promised when I get to it, or feel like it especially when I know that person is depending on me.
Of course sometimes something will happen where you can't be where you said you would when you said you would be or do what you promised when you promised you would. If that does happen, I always get in touch with the person as soon as I know there's a problem/conflict and explain why I can't honor the commitment at that particular time. I offer alternatives in terms of rescheduling, having someone take my place if possible, or reimbursing for expenses if necessary and I always, always apologize.
How depressing that so few people seem to feel the same way when they make a commitment to someone.