"Endless repetition" refers to something that is repeated over and over without ever stopping or changing. It suggests that there is no variety or newness, often leading to boredom or monotony. Full definition
The subject matter of each is enhanced by seemingly endless repetition of the forms, giving it a new depth that is unique from his efforts with his paintings. (juxtapoz.com)
Only some event that may achieve once for all what sacred violence attempts by endless repetition. (religion-online.org)
You don't need to waste your precious time sitting in a gym doing endless repetitions. (isometricsstrength.com)