Header bidding can slow down page load times because each additional header partner leads to more concurrent requests with varying timeouts. This can be addressed by using server-to-server integrations or capping the number of headers per page. Implementing header bidding also requires development resources to integrate directly onto pages, though some partners refuse to use wrappers, so publishers may prioritize key partnerships. Server-to-server integrations can be costly for supply side platforms to develop and maintain connections with multiple technologies.