I think it varies depending on what kind of bills you have. I have always followed the 50/30/20 rule. After taxes, no more than 50% should go to fixed bills like house, cars, utilities, and so on. 30% should or can go to wants like eating out, nice clothes, or "toys". 20% should got savings like retirement, investments, or savings account. Some may not be able to make 10% fit within that 50% of fixed bills while others may be able go a little higher because they don't have as many fixed bills as other people.
