Personally, I started off about 2 months ago and I picked up a level 8 trainer very quickly. I think level 8/9 is about the highest there are so far so you should take your chances on them. There is definitely a huge difference between a level 1 trainer and a level 8 trainer, according to my experience. However, I don't know the difference between a level 5/6 compared to level 8/9. Generally, I think it is quite affordable and would recommend it. With 2 games per week, my salaries of level 8 trainer and level 8 doctor is paid off through one game with extra income. Good luck deciding.