Without periodic recoating, this is an example of the damage that can happen to a stained concrete floor as the sealer is worn through or delaminates.

Without periodic recoating, this is an example of the damage that can happen to a stained concrete floor as the sealer is worn through or delaminates.

A certain amount of abrasion and scratching from foot traffic, playing children, pets, heavy stationary objects, and carts or dollies, cannot be avoided and will eventually erode the existing floor finish on a decorative concrete floor. This finish needs to be restored periodically so that the concrete sealer, and concrete stain below, is not affected. How often to recoat depends on the building environment. In homes, once a year is a good rule of thumb; for businesses, it should be more often:  probably every 4 to 6 months.

You should use a commercial grade floor finish from a janitorial supply house, and not one from a hardware or grocery store.  Apply with a garden sprinkling can and then spread with a lambswool applicator, or loop end mop, in thin, uniform coats. Be aware that loop end mops used for applying finish are slightly different than those used for damp mopping:  they are made of a finer fiber such as nylon filament yarn or microfiber.  A new coat of floor finish does not take long to apply and usually dries in 30 minutes or less. If you have the time, consider applying a second coat of finish, at the same time, for added durability and longevity.  If there is a Decorative Concrete Scoring Pattern on the stained concrete floor, be careful not to fill the saw cuts with floor finish.  Floor finish goes on milky white, and it may end up collecting too deep in the cuts to clear up as it dries. 

Floor finishes are inexpensive - around $20 a gallon from a janitorial supply house. They come in matte, satin, or gloss versions, depending on the amount of desired surface sheen, and vary in optical clarity and depth, as well.

"Spray Buffing" is an alternative recoating method.  It is a short-cut that combines damp mopping and recoating with floor finish. By using a certain type of floor finish, formulated with a detergent, you can remove scuffs, scratches, and dirt, and restore gloss at the same time.  Spray buffing is very effective for maintaining high traffic or wear areas, but it can only be done a limited number of times before adding more floor finish is required.  It is as simple as spraying affected areas and then using a low speed floor buffer fitted with a red polishing pad to work the material into the existing floor finish.

"Hazing" is a common problem with floor finishes caused by:  1) excessive humidity during application; 2) applying additional coats before previous coats have fully dried; or 3) applying over a dirty or contaminated surface.  "Powdering", or chalking, of a floor finish is caused by:  1) applying under cold conditions (below room temperature or near poorly insulated exterior walls or entrances); or 2) applying over an unsealed or excessively porous substrate.  These problems can be resolved by stripping the floor finish, correcting the source of the problem, and then re-applying more finish.

Read more, here, about Decorative Concrete Floor Finishes, and how they differ from Decorative Concrete Sealers.