As property professionals, getting it right first time sits at the heart of all that you do. But mistakes do happen and complaints are made. Ombudsman Services: Property (OS:P) is the ombudsman scheme appointed to handle complaints from domestic customers of RICS members. OS:P handles around 1200 property complaints a year and often common themes run through the complaints it sees. This paper looks at how to handle a complaint as well as where the most common complaints are happening. The paper discusses how effective complaints handling can positively influence the outcome, and also analyses where complaints occur most frequently offering tips to prevent the common mistakes investigated by OS:P.