They can charge you for it if the conditions (e.g. stains) requiring the cleaning, etc. exceeds what would be normal "wear and tear" for your tenancy (e.g. for someone living there as long as you did). For example, extra carpet cleaning is often required when there was a pet or a smoker, to eliminate odors; painting may be required for smokers (again, to eliminate odors) or if the paint was marked up/drawn on by children or chipped/scratched by moving furniture; etc. If you disagree and feel they are charging you when there is only normal wear and tear (which they can't charge for), either don't pay the money, wait to see if they sue, and if they do, defend on the basis that you did not cause damage, staining, odors, etc. requiring the extra work; or if they take the money out of your security deposit, you could sue them for its return.