A few years back I wrote that one of the most important things a personal trainer does for you is answer the question, "What now?"
You plateau. You stop making progress - or make negative impacts on your fitness. You change your goals and don't know where to go. Or you get hurt.
That is when having a personal trainer and a coach helps.
You can see this with Ryan Nie and his client in the post below:
One of my Olympic Weightlifters hurt his ankle [. . . ]
Hurt ankle, but a sport that is exclusively performed on the feet?
You get lift variations that take the ankle out of it without sacrificing practice of the essential elements of his sport.
That's a perfect example of what we do - he with a weightlifter, myself and others with out clients. When everything is straightforward, you can wonder, why do I need a professional to tell me what to do? When things go wrong, that question is answered.