All the time. I have several different conditioners that I use. I've actually narrowed down my favorites but still experiment occasionally. For my rinse out conditioners and DT conditioners I love, Tresemme naturals (moisturizing), Darcy's botanicals pumpkin seed conditioner, GVP conditioning balm, CJ curl rehab, Kenra moisturizing, suave and Vo5.
As far as a leave-in, I alternate between using the above mentioned or CK satin roots, MD red clover, Oyin HH/HD (don't know if I will reorder), and SM hair milk. It just depends on how my hair feels that day, what the weather is doing, and what scent I prefer.
I'm also testing out Giovanni direct leave in and KC knot today. I'm thinking of ordering a liter of the Giovanni smooth as silk conditioner, I used to love it when I first went CG.
As to why? My hair sometimes needs more or less conditioning and the various conditioners meet the different moods of my hair. I like to have conditioners from light to heavy for that reason. I also like having at least 2 conditioners that I can pick up locally just in case I'm ever in a pinch. I've tested a ton of conditioners and have found that I love these, they never let me down. One thing that I look for, other than performance, is the option to purchase bottles in larger amounts. Also, a good conditioner that is multi-purpose...as a RO, LI, DT, and for co-washing.