A frequent question I'm asked by girls when preparing for their session is: should I put a tail extension in? My answer... it depends! Here's a flow chart I made to help you get to the final decision:
To expand a little on this, what I mean by show horse is a horse that you would normally use a fake tail for, like AQHA, APHA, ApHC, etc. breed shows or reining. Of course some breeds like Arabs, Morgans, or Friesians don't wear fake tails, and neither do disciplines like barrel racing.
Another question I'd like you to ask yourself is if your show horse is retired? If they are and have been retired for over a year, I personally would keep them completely natural- meaning no fake tail, no bands/braids, and no show attire or tack. That's a personal preference, of course! In the end, the photos are yours so you can do whatever you'd like!
Some general tips for fake tails:
Make sure it's freshly washed! This is very important because you don't want it to be dirty, clumpy, or have any kinks. A straight, clean tail is a must (in my opinion, of course).
The first tip goes for their real tail as well- straight & clean. By straight I mean not just taken out of a tight braid!
Make sure it's inserted at the correct hight. A general rule is to put the tail right at or a little above the fetlocks.
Always, always, always cut your horse's real tail to match exactly to their fake tail.
Need help on deciding what to do with their mane? Read this post.