I don't brush my girls tail very often and its quite thin, not too bad though. I guess thats just her and shes a TB. I pick feet out every day just incase theres something likely to cause a problem.
Definitely dont brush his tail every day because when i do it takes ages! Although registered warmblood my horse has the hair, mane and tail of a shetland pony, thick and curly. This sounds lovely but unfortunately however brushed, conditioned etc it has turned into dreadlocks within minutes!!!!
Like to think i pick out his feet every day but have to be honest sometimes i dont!
Brush every day now he is in at night - can't stand the shavings in his tail - but use mane & tail every couple of days and it is no problem, it is fairly thick. Pick out feet every day too. Only do these things in the summer when he is ridden.
Forgot to add: only do Shetlands when they come in on the yard so usually a big job!
Mine have their tails brushed daily, and they are spritzed with detangler to prevent split ends. They all have lovely full tails and i never find combing them through makes their tails any thinner tbh. I also pick all of their feet out daily to take out any stones and to check for any problems such as thrush etc etc.
I never brush my horses tails unless its a special occasion and they all have lovely thick tails. I only pick my horses feet out when i ride them- and i have never ever had thrush or any problems.