I'm not so sure they do. Have you ever seen those women with the really really long nails? Kind of scary if you ask me

I think it is genetically determined how strong your nails and hair are..

Mine dont stop growing i have long nails.

My partner is a retired hairstylist and he tells me that hair on the head grows an average of 1/2 inch a month..and continues to do so unless/until some illness or other prevents it. That is why some people have extremely long hair..they just don't cut it. My hair is fairly long and was 12" longer last year, but he cut it for me and gave me a perm. You could contact a local Cosmetology school if you are having a specific problem with this..someone there might be able to help you. About fingernails, mine keep growing and I keep filing them. :)

"How does the growth of hair and nails take place?" "A typical mammalian hair consists of the shaft protruding above the skin, and the root, which is sunk in a pit (follicle) beneath the skin surface. As the cells are pushed upwards from the follicle's base, they become hardened and undergo pigmentation, i.e. coloration. Thus a part of each hair extends below the surface of the skin. This part lies in the hair follicle. The end of the hair, called the bulb, is the only living part of a hair. The cells of the bulb divide rapidly and account for the growth of a hair. The hair cells above the bulb contain a form of keratin called hard keratin. As already mentioned above, the colour of hairs is due to the presence of certain pigments, which are, incorporated from melanocytes a type of specialized cells. Human hair grows at the rate of about one-third of a millimetre a day. The growth of hair in the follicles occurs in cycles. In each cycle, a follicle goes through a growth phase and a resting phase. A hair stops growing during every resting phase, when it is known as a club hair. The club hair remains in the resting follicle until the next growing phase. During the growing phase, the club hair is shed as a new hair grows and pushes it out of the follicle. However, the activity of the hair follicles in the scalp is not synchronized, so that about 50 to 100 hairs a day fall-off from a total of around 150,000 follicles. There is evidence of seasonal fluctuation, with the greatest hair loss in late summer and fall. A follicle may continue its activity for a long time, and hairs sometimes grow for several years and attain considerable lengths. A nail is also made up of keratin. It has three parts, the matrix, plate, and bed. At the base of the nail, and part of the way along the sides, the segment embedded under the skin is known as the matrix. Thus like a hair follicle most of the matrix is covered by skin. The plate is the hard outer part of the nail. It consists of many layers of flat, dead cells that contain keratin. The skin beneath the nail, known as the bed, is like any other skin except that it contains elastic fibers. These are connected to the nail to hold it firmly. The cells responsible for the growth of a nail are formed in the matrix. Newly formed cells push the older ones toward the tip of the nail. This pushing process results in the growth of the nail. The length of hair or a nail depends on the length of the growing phase of the follicle/matrix. Since follicles/matrix in different parts of the body vary the growth rate of hairs/nails also vary. While the scalp hairs are active for two to six years, and then they rest for about three months those in the eyebrows and eyelashes, grow for about 10 weeks and then rest for 9 months. No, it is not true that the hair continue to grow even after death- what happens is in fact that after death the skin contracts and some of the hair which is below the skin surface gets exposed, which we perceive as hair growth." Source and further information: http://www.scribd.com/word/download/2463?extension=doc

The overall growth of the nail within one month is approximately 3mm. However this does vary from person to person. To completely out grow a nail can take up to 6 months. As mentioned, growth rate does vary from person to person, there are many contributing factors such as; weather, health, age and a well balanced diet. The nail tends to grow faster in our early years, reaching its peak around the age of 10-14 and then the nail growth gradually slows down, as we get older. Growth is accelerated in the summer, during pregnancy and during sleep. Poor blood circulation, malnutrition, certain illnesses and some medications can slow down the growth rate. Each nail grows at a different rate. The smallest nail that we often refer to as our “pinkie” is the in fact the slowest, then the thumbs. The index finger generally grows at an accelerated rate in comparison to the others.

they would grow forever unless you are dead, and even then they keep growing for awhile.

You're alive, they grow.

My finger nails growing faster than foot nails, and my hair growing lon every 2-3 week. I cut my nails every week coz I don't like long nails. Nails are growing fast from your fingers, because everyone use their hands working or doing something almost non stop in each minute in each day. However foot nails don't grow as fast as finger nails. There are almost impossible for hair, and nails stop growing, but I knew a woman when I was in elementary school. Her nails stop growing was because she had break her nails by accident or injury. Really disgusting when I saw her nails losted first time. I haven't see anyone has hair stop growing, but I see someone in high school his hair are all white.