All my frequent travel on the same route is for work, and so I have to use the company-mandated travel agent and company-mandated online travel and expenses system, so I just book a return when I need to. The terrible user interface of the online system and impediments of using a travel agent who doesn't take instructions from me and isn't there for my convenience is a complete disincentive to try to do anything more cost-efficient.

I suspect I'm not alone in this.