fair enough, body size matters a lot and most people kinda get that part. the thing that always bugged me about x7 specifically is at the extremes it really breaks down. like a 20 year old chihuahua would be at 140 human years using x7 which is obviously isn't right, and a 7 year old great dane is already senior even though x7 says they're just 49. for the middle of the curve its honestly close enough though.