yes
Some carpet can be repaired easier than others. Most can have a section replaced if you have some of the same carpet or perhaps a piece could be taken from a closet or from under a piece of furniture.
A landlord can charge for excessive wear and tear on carpet only if it's unreasonable wear and tear. After five years, according to national standards, a carpet is deemed to be completely worn, and such wear is considered reasonable. So in answer to your question, the newer the carpet, the more the landlord can charge if the carpet is damaged, if it is damaged outside the reasonable wear-and-tear limits.
I dont know about in California but in the UK it's your own responsibility to clean your own carpet, wear and tear should be replaced by the landlord but if its dirty and you made it dirty then you need to be cleaning it!
Some places have certain stipulations for how often carpet must be replaced in a rental unit. Others will replace only when it is needed. Call someone locally to learn your tenant rights.
Only if the carpet sustained damage above the standard of normal-wear and tare. Fraying carpet, dirty spots, and loose carpet nails are all considered normal wear and tare and are exempt from damage claims.
With words and in a language that you and your landlord both understand
Not necessarily: he can have the carpet professionally cleaned.
If there is a provision on the lease which requires that your carpet be cleaned six months prior to the expiration of the lease, then the landlord has the right to enforce those provisions. Additionally, if the carpet is damaged or dirty because of obvious abuse by the tenant and not the cause of normal wear and tear on the carpet, the landlord has the right to demand that the carpet be cleaned. However, if the carpet was not brand-new, then whatever dirt or damage occurred to it is measured according to wear and tear by the age of the carpet. Carpeting of five years of age or older is usually deemed to have reached its maximum age, for which the landlord has no claim. Finally, the landlord may not keep your entire security deposit simply because you didn't clean the carpet: he can only deduct the cost of cleaning the carpet from the security deposit. I doubt that your landlord can evict you simply because your carpet is dirty. If you have only been in your apartment for six months and your landlord evicts you because the carpet is dirty, then I would take pictures and present them to court to fight your landlord.
When damage exceeds what the law calls 'ordinary wear and tear' Since tenants' interests in real property are not vested, the opinion of the landlord carries the most weight in such a determination.
Not anywhere I know of.
I have had all (£300) of my deposit taken in the past for a soiled carpet. But usually, where it is a case of simple dirt and not damage, the landlord should only take the amount required for cleaning (approx. £50-£100). Carpet shampooers can be hired from rental shops for as little as £30 per day (shampoo included) and can make a big difference.
It sounds like their house could use a renovation. Replacing the carpet and repainting the walls would be a good way to freshen up the space and give it a new look. This could increase the aesthetic appeal and potentially even the value of the property.