Unfortunately 4 years old is like 50 in human years for a Great Dane. My cousins had one and he lasted I think it was 9 years.... In the end he was very arthritic and ended up with a bone problem and tumors. They had to have him put down. However, at least half a dozen times he ended up in the vet for well over $2000 tabs. I would steer clear if you're concerned about cash in any way. They're not cheap to maintain.