Actually, I don't deep condition. The funny thing is the ingredients in conditioners are often the same ingredients that are in deep conditioners. It's just sometimes they are in a different order, or in different concentrations, or greasier. Or they add extra sticky ones to the leave-in products. It's just that they charge you more for a smaller bottle of leave in product that's basically the same as the conditioner.

It's all about marketing. Manufactures can sell more bottles of product if they repackage the same basic ingredients over and over and tell you they are for different things, like deep conditioning, conditioning, conditioners for dry hair, colored hair, damaged hair, permed hair and as a leave in. Often, these all have nearly identical ingredients, just in different bottles and for different prices.

For extra conditioning, sometimes I put a little olive oil or coconut oil on my ends before braiding my hair up at night. You could also put about a teaspoon of olive oil (or another liquid oil) in a full bottle of (good) conditioner and shake it up really hard before combing it through your hair and leaving it in. I used to do it when I first started leaving in the conditioner, but after a while I realized I didn't really need to do this (well, that and I'm kind of lazy).