Did you train Tara yourself? How old is she? At what age was she fully trained? Does there come a time (age) where they lose interest in hunting, or where you need to retire them?
Good questions, I'll take them one at a time.
Q1: Yes I did train Tara myself, and my previous gun dog Molly (RIP 2015). But I did make sure I myself was trained to train a dog, very important. This means investing in reading retriever books and buying retriever dog training videos, and, most importantly, having a pro trainer observer your training and give tips. With Tara I paid a pro, probably 10 or 15 sessions, to watch me train Tara and give tips/guidance. I did the same with Molly, but with Molly I joined a Hunting Retriever Club (HRC) for help. With Tara I did not have time for HRC, but recommended for those budget conscience.
Q2: Tara was born Aug 2016.
Q3: A pro will tell you, probably 2 years. That is running through their program. I will tell you the training never ends, every day I train my dog. this will go till the day they die. But retriever training goes like this. 1 to 6 months, it is all fun, fetching (which they do instinctively, you do not have to teach this), here, heal and sit. These are most important. Then you have "No" also very important.
At 6 to 9 months (keep in mind dog is like an 8 year old kid here), this is where you teach your dog the concept of "force". This means when I say sit, you don't just sit, you sit fast, same with all commands. This is where the electric collar comes in, and collar conditioning is very important it is done correctly, otherwise you can ruin a pup. At this most important level of training, the pup needs to know they are in control, they sit fast, no correction, they do not sit fast, there is a correction.
Then you have gun fire training, some pups you can fire a gun in front them and they are fine, other dogs you can ruin them, and they turn gun shy, and very hard to fix this. So you need to be safe, start with a cap gun, get pup used to fetching and smelling gun powder, go to blank gun, etc.. baby steps...
1 year your dog should be ready to hunt.
Q4: They never lose interest, they may not get as excited as before. This is really not fun for me to talk about, gets me misty eyed, but yes there will be a time you do not take your dog hunting. You have to know your dog, and their capabilities. Your dog may be old, you take her on a hunt, but only send her on simple retrieves that she is capable of doing, that she will enjoy doing. Don't take shots where duck lands 100 yards away, pick your shot, or retrieve the duck your self. Teach your dog early on, they do not have to retrieve every bird. Dove hunting, in the Texas heat, when I know my dog is over heated and needs a rest, she watches me retrieve a dove or 2. They see this and know Daddy knows best.