Nail growth will vary enormously depending on your dogs lifestyle.

A dog that does a lot of pavement walking will naturally wear down his nails. The back nails are often shorter than the front, a dog exercised on grass may need regular attention as will light weight breeds.

Long nails are unsightly and can cause long term damage to your dogs feet. A dog with very long nails can cause the entire tendon & bone structure of the foot to weaken and the toes to splay causing irreparable damage.

Unattended dew claws will curve back into the pad, causing a puncture that can become infected.

Some dogs especially working breeds such as Springers and Cockers benefit from having some hair between their pads for protection while they scurry through the undergrowth. However, some people also believe that by trimming as much hair as possible it will help to prevent grass seeds from taking root.

I routinely trim away as much hair as possible as I do actually believe this does help to prevent grass seed problems and clumps of mud sticking to the paws. Not all dogs will tolerate their paws being attended to extensively, something the owner can do to help is to regularly touch their dogs paws especially as puppies by actually putting your finger into their pads checking for mud lumps and grass seeds. If they become used to this they will be happier for Vets and Groomers to touch their paws.