Hi Susan!
Thanks for stopping by.
From what I know about amaryllis, first, they aren't really amaryllis but a true bulb known as hippeastrum; I have no idea why we call them amaryllis :-> Connie is correct in that they prefer to be in a "tight" pot, but I would think after 8 years, they are truly pot bound. The rule of thumb is to repot every three years. In addition, have you given them fresh soil during the 8-year period and do you feed them regularly? After 8 years, if you haven't given them fresh soil, I would think everything is gone from the soil they are planted in. You also need to feed weekly once the bulb has started to show signs of growing. One-half strength African violet food is a good choice. Good bulbs can live and bloom for up to 75 years, so I don't think there is anything wrong with the bulbs unless they got too much water, so when you take them out of the pot, check them to be sure they are sturdy and don't have any mushy spots. I would just repot them and treat them like you always do - don't let them dry out.
Good luck with them and let me know how things turn out.