This is another case of how different each horse is from another.
I'm careful grooming tails - I hate pulling out hairs. So, for most of the late fall, through winter, and into spring, I don't groom tails, at all. If there are burrs or mud, I pick it out with my fingers.
Usually, the first really hot day in late spring, the horses get one of their few shampoo baths, including tail washing, and after that, I brush out tails, with liberal application of Show Sheen, and then use Show Sheen every time I brush tails after that. This year, for some reason, although we had baths, there was no tail brushing.
So we ended up with September (and early October) tail brushing. Dawn was easy - her black tail is sleek and slippery, even without Show Sheen, and easily brushed out. Her tail looks a lot better than it used to - she used to frequently pull out big chunks of it catching it on her water bucket hooks, but that seems to have eased up with Missy (instead of a gelding - nasty gelding, Dawn says) in the adjacent stall. Pooping in the water bucket is also way down, which I appreciate. Her tail is pretty full now, and hangs to almost fetlocks, which is longer than it used to be. (None of these photos is recent, but it gives you an idea of tails.)
Red's tail is beautiful - very dark in color (although his mane is lighter than his body color), and quite narrow and long - it just brushes the ground. It also has some wave to it, and tends to twirl - individual tendrils tend to form long, wrapped twirls, which makes them tough to brush out at first. It took quite a while - at least an hour - to work through his tendrils.
Pie's tail is huge - very large and bushy and also quite long - it almost touches the ground. I knew it would take quite a while to brush it out - his hair is a bit curly/kinky and tends to form knots and clumps, and it takes a long time to work through all the hair volume. But once it's done, it's full and exuberant. It took me two full sessions - probably an hour each time - to get it done - and I have to brush it with Show Sheen every day to keep it from snarling up again.
Missy has the prize tail - it's full, and very thick, and very, very long, white on the top and very dark brown below - it drags on the ground by at least three inches when she's at rest. I was dreading brushing it out - although her's had been done more recently that any of my other horses. But it turned out to be a breeze - less than 10 minutes to get the whole thing done. She has the same slick, very straight hair that Dawn does - no curls or twirls or snags to deal with. It look gorgeous - I may have to (reluctantly) trim the very ends to keep her from stepping on it and pulling it out. She seems to have the same slippery, dirt resistant coat and mane/tail hair that our pony Norman has - we called him the Teflon pony - which is a good thing, considering how much white she has.
It's interesting the different character each horse's tail has - have you found that with your horses?