1. If your utility bills only seem to be increasing each month, there’s a good chance that new siding would help with it.  New siding would be more effective at insulating your home, and with new siding you can add more insulation that will help.  One way to know that your siding isn’t working as well as it once did is if your home feels more drafty, especially near outlets or windows and doors.  Some siding is even rated by Energy Star for advantages in its efficiency.  This means that you could eliminate drafts and significantly decrease your monthly utility bills.
   
2. Are there cracks, or is there any warping?  When there are flaws in siding, it not only makes your home or building lose curb appeal, but it adds more risk to the safety of it.  Holes or cracks could pose the threat of moisture creeping in and damaging more than just the outer exterior of your home.  More than water and the damage that can cause, holes and cracks are inviting for little pests.  Bugs and animals may be able to make themselves at home when there are multiple entry options.  Warping can also be an indicator of unseen problems and hazards.  Replacing siding becomes crucial at this point.
3. Flawed siding can let more moisture in, and the only threat isn’t just damaged wood.  When mold and mildew are growing in your home or building, they become a threat to the health and safety of everyone who enters the structure.  Moisture and water may not just be getting in through cracks and holes.  Sometimes siding is just old and needs to be replaced, along with insulation.  

If you have any of the problems mentioned here, call an expert to come check out your siding and introduce you to the options you have.  Chances are, new siding is in order.   They can help you determine which kinds to get for the area you live in and for the specific issues you are experiencing so you don’t run into them in the future.