Siding typically lasts for decades. Since it is so long-lived, homeowners sometimes forget to keep an eye on it for signs of damage. But since siding does not last forever, it's important to occasionally give it a once-over and see how it is doing. If you notice any of these signs, then your siding is probably nearing the end of its lifespan and is due to be replaced soon.
Look across the horizontal pieces of siding. Are there any gaps between them? If there are, that means water is able to penetrate your siding. This is the very thing that siding is intended to prevent. So, if your siding has begun to gap, it's a good idea to replace it before you end up with extensive water damage behind it.
Rot or Deterioration
If you have wooden siding, then you need to be on the lookout for rot. It may just look like black or brown blotches on the surface, but if you press on those spots, you may notice they feel a bit soft. Rot not only compromises the strength of your siding, it also invites insects like carpenter ants and termites to eat the material.
If you have siding made from vinyl or aluminum, then you don't have to worry about rot. But you do need to look for deterioration general. Vinyl siding can grow brittle after years of sun exposure, and then it may start chipping and cracking. Aluminum siding doesn't rust, but it can eventually corrode. If you see corroded patches, that means your aluminum siding should be replaced soon.
Have you noticed little drops of moisture along your interior walls, or perhaps behind your baseboards? This water may be getting driven behind weakening siding when there's a storm or rainfall. If your siding also shows signs of damage as discussed above, then you can assume it's the culprit. If you can't see any physical damage to the siding, then consider having a siding contractor come take a look. They may see damages that you overlooked, or they may find that the water is coming from another source.
If you think your siding may be reaching the end of its lifespan, then it's time to take action. Contact an exterior siding company, and get their opinion. If they also think you need new siding, they can give you a quote and help you explore your various siding options.