In matters of permissibility regarding men's ear-piercing, there is no significant difference between piercing a single ear or both ears. The debate revolves around the act of ear-piercing itself, regardless of the number of ears pierced. Whether one ear or both are pierced, it is advisable to follow the guidelines and considerations provided by Islamic scholars when making a decision. Ultimately, seeking knowledge and understanding from trusted scholars can help in forming a balanced perspective on the issue.