I have hair long enough to sit on. I baby it and it's in excellent condition but I don't even remember the last time I did a DT. I am planning on doing one tonight because I made the mistake of putting a small amount of lemon juice in my henna mix last weekend. I know my hair gets straw-like with lemon juice. Duh. Generally though, they are not necessary for me.
3a/b, fine, lots of it