Dyson included two air filters after the suction motor to ensure only clean air was returned to the room. Dyson also claims that they need no service for the life (10 years?) of the machine. The way that I treat mine, I believe that I'll never need to touch them.
A cousin of mine owns the Ball Animal which has more suction power (and more noise!) than this Dyson Cinetic Big Ball Animal. I was impressed enough with hers that I bought this one. She must regularly wash, rinse and dry two filters, placed one before and one after the suction motor. I empty my bin often and even wipe out the interior of the port so that the bin door closes against. Some owners will not empty their bin until dust and debris are at or above the maximum fill line, but by then, the weight of the material has compressed and compacted the waste enough to create an overload.
Using this vacuum reminds me of the purr of a heavy, powerful luxury car. A benefit of the self-adjusting cleaning head means that this vacuum tends to leave my throw rugs in place rather than try to pluck them from the floor or carpeting!
Bottom Line: Yes, I would recommend this to a friend