Part of this morning's guitar practice consisted of playing this chord progression from Fernando Sor étude number 17 100 times with a metronome. The number 17 refers to the piece as published In Andres Segovia's book and not Sor's actual opus number.
The progression is not difficult but requires quick shifting and positioning of the fingers. I tend to get lazy and thus is one of those spots where I have been sloppy in playing the piece. I should also mention that I practice such things in sets. I will do the progression five or 10 times in a row and then pause for a short bit before doing the next set of five or 10. It is much the same way as a weight lifter practices in sets to gradually build up strength, endurance and accuracy.