I booked the outbound 3 days in advance. The outbound was last week, and I booked back-to-back tickets as I had two trips over two weeks.
Most of the time when I book by the time I get around to it, the fare difference is roughly £150. Using your example, I would agree with you it is not worth it. However, when I know my plans are fixed and I can use the back to back, I go in Club if it stays within £120-150 range.
I guess we all value things differently, but that is not the same as needing to have my head fixed 🙂