Common mistakes include using someone who is not properly regulated, accepting promises of a guaranteed visa, and failing to ask for a written fee estimate and clear scope of work. Errors can also arise when an adviser misses deadlines, submits incomplete evidence, or does not check that information in the application is accurate and consistent. Check whether the adviser is a solicitor regulated by the SRA or an immigration adviser regulated by the Immigration Advice Authority. If you are concerned about an error, ask for an explanation promptly and consider independent advice about complaints or your next steps.