Meh, I have 6 disk drives. I plan ahead since I build rather static projects. (i.e. they are designed to project the needs of my world. This is also called engineering.)
I have two almost filled with 4k drives. Though I am putting all my dirt, cobble, sand, stone, wood, etc. into 12 additional DSU's for space efficiency purposes. It's better to plan ahead, though it doesn't look like you put a lot of thought into placement or design. It'll matter when you do some project planning/management though. Waste less time fixing things you didn't consider/think ahead about.