I have to agree with you. Taking steps to ensure that disk space is not wasted is definitely beneficial.

But there is a counterbalancing point: Disk space is normally cheaper than problems that can be solved by sacraficing disk space. I hate wasting disk space and the increases in IO time that it brings, but I will trade vast swaths of disk space for even very small performance gains and normally say it is a good trade.

When I am thinking about the trade offs for creating an index, I will consider carefully how often the table is written to and the trade offs in write performance, but I won't give a second thought to the disk space because it is cheap relative to making my users wait. I will create complicated and large indexed views in the same way.

Similarly, I tend to log procedures extensively. This costs disk space, but that disk space is cheap compared to having a problem in production and not being able to track down in detail when, why, how, and who caused it along with enough information to know what the answer should have been.

So, I agree, it was a good article with a good point and one that developers and DBAs should remember. I just want to caution against taking it to an extreme. Disk space should never be wasted, but at least in the situations I regularly see trading disk space for detailed logging or improved perofrmance is almost always a good trade. Disk space is cheap enough to justify that.