For over a year I was fighting to keep my cable adjusted so the indexing would match up and I'd be able to shift through all my gears. Specifically, the cable needed to be tightened periodically, it always got looser over time. That might have been enough information by itself..

Eventually it got sticky and I could no longer access the tallest 4 gears, even though the rear-derailleur seemed to have enough spring and the brifter would shift if I pulled on the cable. But it wasn't road-worthy, so then I had to get off my lazy duff and find out what was wrong.

The shift cable was frayed inside the brifter housing, and was down to 2 strands. I cut it, removed and replaced. $5 and half-hour later, it was all tuned up and shifting easily from top to bottom.

I presume it will last a long time, and stay in tune a lot longer. But how does a shift-cable get chewed up inside the brifter anyways? It seems like it had to have been a faulty cable or someone pinched it hard during installation. (Used Windsor bike I bought almost new in 2008.)