The Bilsteins are (or were) guaranteed forever as long as you owned the car. If you plan to keep your Volvo for years, consider a local vendor because if one of the strut inserts fails, you can easily replace it. Of course, if the vendor disappears, I am not sure what you can do, but it may be harder to send a bad unit back to a mail order place. I had this experience with my 1981 BMW 320i, where my mechanic installed Bilsteins in 1988 or '89. One of the rear units began to leak. The replacement part was, indeed, free, but I had to pay for the labor. I had the repair receipt, so there was no question that I had bought it a long time ago.