Ive learned a lot from clipping dozens of nails 5 days a week for the past 4 years. lol first of all- all breeds have different types of nails. some breeds' quicks never grow, or they grow slowly anyway, so even if they are long you can cut them way back (rottie and german shepherd for example). however, many breeds' quicks grow with the nail, so if the nail is too long, you may only be able to cut a small amount at a time (pugs and beagles for example). a dog with the latter type of nail needs to have tiny amounts trimmed off every couple days in order to get them short again. also, different dogs' nails grow at different rates. some need them trimmed every 2 weeks, others can literally go every 2 months. also depending on the shape of the foot/toes and the dog's gait, the nails may be longer/shorter depending on how much get worn down by walking. so basically, it all depends on the dog. my personal opinion as an anal nail person is cut them as short as you can without hitting the quick. and when the dog is standing still the nails should not hit the ground. the length you showed is perfect and typical of properly trimmed dobermans- their feet are shaped as such so the nails are a lot closer to the ground than most other breeds, so their nails should be shorter. german shepherds and pit bulls for example tend to have flatter feet so their nails are farther from the ground and tend to be longer.