Review on Fette Filter - High-Efficiency Pre-Motor and Post-Motor HEPA Vacuum Filters Compatible with Dyson DC14. Compare to Part # 901420-01, 905401-01, 923480-01. (Combo Pack) by Ashley Belehar

Finally after more than 15 years they broke down and replaced the filters. I will say I should have done this 10 years ago, the vacuum cleaner is like new now I can't believe the difference between the old clogged filters. If you're thinking of replacing filters, don't wait and replace them, I plan to change them annually. It is also very easy to install, anyone can do it.