There is no official, universal success rate for family law solicitors, because outcomes depend on the facts, evidence, negotiations and decisions of the court or other parties. A solicitor should not promise a particular result, and many family cases settle privately rather than producing a simple win or loss. Ask about their experience with cases like yours, likely strategies, risks, timescales and costs, and how they assess outcomes. You can also check that they are regulated by the Solicitors Regulation Authority and seek an initial view from a suitable regulated solicitor.