Your home's blinds provide you with protection from sunlight and UV rays and also help you maintain your privacy and the temperature within your home. However, like all parts of your home, age and use can cause them to become worn, less effective, and less aesthetically pleasing. Knowing the signs of damaged or worn blinds can help you have them replaced once they begin to near the end of their lifespan.
Inability to Close
If the slats of your blinds won't come together tightly, and, instead, they leave a small gap that lets light through, they should be replaced. The gaps reduce the overall effectiveness of your blinds, as they still allow heat to enter your home and won't block prying eyes from outside. This is can be caused either by wear on the slats or the cords, but either cause will result in the same thing.
In a similar vein to the above point, if your slats are physically warped or damaged, you should look into replacing your blinds. Warped or damaged slats can prevent your blinds from adequately closing, letting heat and light into your home, and can also cause increased wear on the cords holding the blinds up, making it much more likely that the entire structure will collapse or fall apart.
This is most noticeable with lightly colored blinds, but any forms of discoloration, yellowing, or mottled shading is a clear indication that the materials of your blinds have begun to break down. Besides simply looking bad, this discoloration indicates that your blinds may begin to physically fall apart or become damaged in the near future.
Keep an eye on the strings that hold your blinds together. If they have become frayed, your blinds are likely nearing the end of their lifespan. Frayed cords are much more likely to snap and leave your blinds unable to open or close, and they can even affect how tightly your slats close before they physically break.
If you have issues raising or lowering your blinds, the mechanisms within your blinds are likely extremely worn and near breaking. Usually, this symptom of worn blinds will also come with visibly damaged or frayed cords, though this is not always the case. You should look into replacing hard to move blinds as soon as you can, as they are often near breaking and can be a major inconvenience when it comes to customizing the amount of light that enters your home.