We've lived in our home for 5 years and have never had our ducts cleaned. I have consistent allergy problems so we though we'd see if cleaning our ducts helped.
We did a lot of research and found that the "coupon" places never really did a great job and typically ended up charging you more than you expected. Ductworks reviews were pretty positive so we decided to go with them.

Juan was our technician. He did a great job keeping our home clean while working. He showed me the before and after pictures before he left. While our ducts didn't seem too bad to begin with, I could definitely tell he had done a good job.

I even received a check from the company a week later saying that we had "overpaid" by $15 dollars, so they were refunding that amount.

The only negative experience I had was that I never received a follow up email with our before and after pictures. When I followed up with the company to see where they were, they didn't seem to find any record of us in their system... that would worry me a bit, but like I said.. the technician did a great job, and I even got some money back from the company.

I have overall been satisfied with the work! They recommend cleaning your ducts every 5 years or so. Based off of the pictures I saw, I think we will probably be ok to go every 7 years or so instead.