How do you know its time to clean your air ducts?

Here are a few things that can alert you that its time to clean the duct work:
1. Accumulation of dust. Have you been noticing a lot more dust than usual?
2. Have you seen your electric bill skyrocket?
3. Does your system sound like its about to explode?
4. Did you undergo any type of construction. Air duct should be automatically cleaned after house construction.
5. Has it been more than 3 years since your last cleaning?

If you said Yes to any of the things above it means its time to clean your ducts!