This is written specifically based on facts as well as personal opinion. My experience is solely in the Pacific Northwest.
Besides the obvious cosmetic reasons, keeping a healthy coat of paint on your exterior and interior surfaces is important.
Caulking and painting both interior and exterior materials is the best way to prevent moisture damage.
Potential Interior Damage:
Swelling on trim and doors – Especially in kitchens and bathrooms. We have replaced many baseboards and window sills that absorbed moisture and swelled up.
Peeling Texture – Texture that is peeling or flaking off is usually a moisture problem. Absorbing moisture and then drying out causes the texture to become loose, first cracking, then flaking. This is often found near showers/tubs and ceilings that have not been painted for 15+ years.
Damaged Drywall – If drywall is not sealed by paint and is exposed to moisture, the drywall will become very soft and need repaired.
Stains – Stains on the walls/ceilings/trim from moisture damage.
Potential Exterior Damage:
Dry Rot – When moisture is absorbed into wood, a fungus grows that feeds off what makes the wood strong, causing the wood to become very soft and “rotted.”
Warping – Extreme heat to siding or trim can cause these areas to “warp” (become bent or twisted out of shape).
Drywall/Interior Trim Damage – This may seem like an interior problem but can also be due to moisture penetrating the home from the outside. If the caulked seams around windows, doors or trim on the outside become broken and split. Water can penetrate past the siding and cause damage to interior surfaces near that opening.
Why Caulking and Painting are the Preventative Solutions:
Most damage that we encounter, interior and exterior, is due to split/failed caulking, or caulking that wasn’t done correctly the first time.
When we paint a home, we inspect all areas and insert caulking in any areas that have already split open or appear to be stretching.
Once all of the caulking is completed, we start the masking and painting process.
Paint is your home’s shield but should only be applied once all surfaces are sound and all cracks are filled with caulk. It is time to apply the paint. Paint protects caulking, all siding and trim materials from moisture exposure and extreme heat.
Paint usually has four or five main compounds. The most important to the durability of the paint is the resin. The resin is the binder that forms a film and holds the paint pigment in place. The resin protects siding and trim from warping and from absorbing moisture. Extender is another compound in paint whom purpose is to improve adhesion and strengthen the outer film (resin).
There are many variables to answer this question, but the short answer is every 6 or 7 years.
Although paint jobs can fail in as soon as 2 or 3 years or even last 20 years. Variables that affect the longevity of a paint job are the quality of paint used, conditions while painting, completeness of preparation work performed before painting, the type of material being painted, and amount of exposure to the elements.
The most important sign is caulk that is separating. Even if you recently painted, it important to keep an eye on the caulk around your windows and trim, especially on the sides that are the most exposed.
On the interior, check around your window trim and base boards in your kitchen and bathroom areas. If you notice split caulking, it is important to re-fill those gaps as soon as possible. Whether you hire a professional like JK Paint or do it yourself, it is important to fill the gaps completely, so that water can not intrude.
When you notice the color in your paint fading, it is time to repaint. Fading occurs when the resin has been worn down by ultraviolet rays. With the resin broken down, the rays beat directly onto the paint pigments and have a bleaching effect.
No extra prep work is required if the paint is only fading, so this is the best time to repaint without accruing additional project costs/time that are necessary once the paint has completely failed and begins peeling.
Usually, fading is first seen on the south and west facing sides of the home. Depending on how fast your paint is fading, it is also smart to re-paint the worst walls more often.
All of the siding, flashing and repair jobs JK Paint & Contracting has done have either been for the entire house, or only the southern or west facing wall(s). Not once, have we re-sided only the north or east facing wall. In all of these circumstances, more frequent caulking and painting would have protected and prolonged the siding/trim. New siding can cost four times more than painting. This is not an exaggeration, rather, a conservative estimate.
Once your paint is flaking or peeling off, it is definitely time to get those areas sanded, caulked, primed and repainted. Peeling paint is no longer serving its purpose to protect the material from moisture and ultraviolet rays. Wood is extremely exposed to dry-rotting, which always requires a complete repair.