Which of the following practices would likely hinder performance at scale in Sitecore?

Poor database indexing is a significant factor that can hinder performance at scale in Sitecore. Database indexing optimizes the retrieval of data, making queries faster and reducing the strain on system resources. When indexing is poorly managed or absent, the overhead of searching for data increases, leading to slower response times and potentially overwhelming the database server during peak loads. This can severely impact the performance of the Sitecore application, especially when it's handling a large amount of content or numerous simultaneous requests.

In contrast, routine system updates maintenance can improve performance and security, effective content caching significantly speeds up response times by storing frequently accessed data in-memory, and the utilization of scalable cloud solutions allows for resource optimization and flexibility in accommodating varying levels of demand. Each of these practices enhances system efficiency and scalability, which is crucial for high-performance environments.