It's much easier to convert older buildings than newer ones, just due to them being designed differently. You lay out structures different if you're designing a

It's much easier to convert older buildings than newer ones, just due to them being designed differently. You lay out structures different if you're designing a small building for PI style offices than you do if it's a huge open floor plan. It's just more difficult to break out those big spaces into smaller apartments while making sure people have enough light.