A great gift for a 75-year-old man would be something that he will find useful or fun. For instance, some practical and useful birthday gifts for dad include a wallet, suitcase, grooming kit, flashlight, mobile phone, and rick rack. These are all things that your dad will find helpful and useful during the day-to-day activities of his life. If you want to go the extra mile for your old man then consider giving him traveler's checks as well. Not only will it make him feel young again but he will also have an easier time when paying for items while traveling in another country.