A home is many things: shelter, a place to create family memories, a comfort zone, an investment. Regardless of the reasons for owning a home, it makes sense to maintain its value so that it can be enjoyed for years.

Day-to-day living causes an inevitable aging process for any home. But an active maintenance regimen, focusing on a few key systems and finishes, can stem or slow that process. And for products, systems and finishes that no longer benefit from maintenance, investing in replacements and upgrades can refresh a room or curb appeal, provide greater convenience and comfort, and perhaps even lower future maintenance costs.

The thought of staying on top of everything in a home, however, can seem daunting. But actually, it comes down to common sense, a bit of diligence, and a short list of critical products and systems, including:

• Heating and cooling. It's a simple thing, but changing the furnace filter every three months goes a long way to maintaining the proper operation of a home's entire air distribution system. A clean filter keeps dust, moisture, and other allergens out of the ductwork to keep the indoor air fresh and healthy. In addition, professionally clean the ducts and carpets every 2-3 years. A properly maintained heating, cooling, and air distribution system can last 15 years or more. Within that time, new technologies will have been established to improve energy efficiency and comfort at a level that likely justifies replacing the equipment.
  
  
• Drainage. Rainwater runoff, among other sources of water, must be directed away from the structure to avoid potentially serious problems. Maintaining a home's drainage and runoff system, however, will mitigate that potential. For instance, gutters should be cleaned out and repaired, as necessary, once the leaves have all dropped in the fall and again in the early spring; downspouts should be fitted with extensions or splash blocks to direct or disperse runoff away from the house. In addition, make sure dirt against the house (called "backfill") is kept sloping away from the structure and that plantings do not grow or root closer than 18 inches from the foundation. A common replacement for aging and leaky gutters and downspouts are seamless systems and those that are designed to keep debris out of the trough.
  
  
• Roofing and siding. A new home's exterior finishes, mainly its roofing and siding materials, are designed to last for at least 20 years. That being said, any cracks, voids, or other damage to these finishes during their design life can lead to leaks and related moisture problems.

Visually inspect the roof and sidewalls of the house at least annually for the first five years, and then every six months after that. And, of course, make any repairs immediately. Replacement roofing and siding is a common upgrade, creating a fresh look for the home's exterior and providing an improved barrier against the elements.

There are other maintenance tasks that can further help protect the investment of owning a home and, perhaps more important, sustain or upgrade its comforts and conveniences of a house. The key is to properly maintain a home's materials and systems until they reach the end of their usable life, at which time they should be replaced to not only restore (and usually improve) the performance of the original, but also refresh the look and feel of an existing home.