A duty to protect one’s client from incurring unnecessary legal expenses?

Yes, a lawyer has a duty to advise and protect a client against unnecessary expense – including the unnecessary expense of instructing the lawyer to do legal work that is “entirely disproportionate to the complexity of the case and the nature of the matters in issue in the proceedings:  Judge O’Brien of the Family Court of Western Australia in Taronite and Mabra (Costs) [2017] FCWA 72, [103]-[108].  In this case  the parties spent in excess of $570,000 in legal fees.  See the case in Jade at https://jade.io/article/533469