Here are some general guidelines:
* Generally, dogs need their nails trimmed every 2-4 weeks.
* If you can hear your dog's nails clicking on the floor, it's time for a trim.
* If the nails are long enough to curl under and touch the paw pad, they need to be trimmed.
However, it's important to remember that:
* Over-trimming can be painful and cause bleeding.
* Some dogs have sensitive paws and require more frequent trims.
* Dogs who are very active may need more frequent trims.
It's also important to note that dogs with dark nails can be harder to trim because the quick (the pink part containing blood vessels and nerves) is harder to see. If you are unsure, it's always best to consult with a professional groomer or veterinarian.