To determine if you have a Holzwurm infestation, keep an eye out for specific signs. Look for small exit holes in wooden surfaces, which are typically about 1-2mm in diameter. These holes are where the adult beetles emerge. Additionally, check for the presence of fine, powdery sawdust known as "frass" near or below these exit holes. The presence of both exit holes and frass is a clear indication of Holzwurm activity. Regular inspections of your wooden items can help you spot these signs early and take appropriate action.