I have a QH with the most gorgeous tail I’ve ever had. It GROWS and it is thick. I usually have to cut off 8 to 10 inches every spring so she doesn’t step on it. I keep it in a TailBoot at all times. I only full brush it when I have washed and conditioned it, and dried fully. That’s maybe once every 2 weeks or so. Because it truthfully takes forever to wash; it is SO immensely thick.
However, in winter (I live in North Dakota), then it’s not washed until it’s warm enough to wash, so usually from October to about April or so. I do tidy it up about once a month during the winter. This was one of those times. Do a light brushing to get some of the snarls out from where the TailBoot wraps in, using Cowboy Magic. Honestly, keeping it up 24/7 keeps the stains out and prevents any of the fairy knots, so it does make it really easy to maintain.
My younger mare in the picture, I was able to achieve a lot of growth with her too, doing the same method. When I bought her a year ago, her tail was barely longer than her hocks. This spring, it was touching the ground!!
Really great progress on hers. Less is more when it comes to tail care!