Doors and their frames are exposed to the elements. Even if you have a storm door, it does not stop some of the affects of time and weather. For example, heat and cold outside can cause shrinking and expanding. Here is how that affects your door frame over time, and why you may eventually need a replacement door frame.
Cracking and Splitting
Shrinking and expanding causes cracking and splitting. Frames are often made of wood to allow for these things to happen, since the house around the frames shrinks and expands with the door frame. Plastic or vinyl does not shrink and expand with the house, so it is avoided unless your home is somewhere consistently warm. However, the cracking and splitting that takes place causes the wood of the door frame to splinter and look unsightly and rough.
Warping also happens to these door frames. You can tell a warped door frame by the way your front door meets it. If you cannot close the door fully, or the door closes and then springs open on its own, the frame is probably warped. (Either that, or you have a ghost, but more likely, it is warped.) This leaves your home unsecured, since the door could pop open at any time and leave everything exposed to an intruder or a thief.
Gaps for Water Damage
As water travels down off of your roof, it could find its way into the gaps created in your door frame via shrinking and expanding. Expanding is made worse if the water in these gaps freezes. Even if the water does not freeze, it will begin to seep into the wood and walls of your home around the door frame. There, it can turn into mold, and create a lot more water and mold damage than you want to address.
Get a Replacement Door Frame Soon
About once every ten to fifteen years, you should replace your front door and/or front door frame. This will help prevent many of the issues associated with shrinking and expanding. It will also save you hundreds to even thousands of dollars in front door replacement, water damage, mold control, and theft.
Your front door protects your home in many ways. Do not leave your home exposed or unprotected by ignoring this necessary homeowner maintenance task. If you cannot install the door yourself, there are window and door experts who can.
Visit a site like http://www.distinctivesidingandwindow.com for help.