The slayers is divided into disks with 6 or 7 episodes on them. This gives one 150-175 minutes of time in-between disk changes.
Ranma 1/2 is broken into disks with 4-5 episodes, delivering 100/125 minutes between disc changes. Not as good as the slayers, but it rarely is that good.
Aria brings 3-4 to the table, or 100/75 but even that is pretty good compared to the normal amount.
Valkyrie drive clocks in at an obnoxious 2 episodes per disk. And, to make matters worse, one disk of valkyrie drive can cost as much as 100$, which is more then FIVE disks of ranma.