How come every tech site review that has detailed components for building rigs always exclude the price of the OS in their total cost? Is it assumed that you would use a pirated copy? I understand that the actual build-up is purely hardware related but it won't do anything other than post without the operating software. And I can bet that most users of an enthusiast rig will be installing 7 or 8.
No we don’t assume you would use a pirated copy. We assume you can work out what operating system you would want to use all on your lonesome. Some operating systems are free so why put a price on it, there are also a heap of Windows versions so that's a guide in itself. Do you already have a paid copy of Windows, are you upgrading?
When everyone does something there is probably a good reason for it, other than pirating
Yes, I already have several copies of Windows. When I do upgrade, I usually keep at least 50% of the parts list, to me that's what upgrading means. When you build from the ground up, do you throw everything else in the trash / recycle bin except for the OS? I think not. Every rig I built from the ground up had the previous rig donated to a family member or local charity, including the OS because I don't pirate software - apparently some folks do. The only free OS isn't worth the headache so purchasing a new OS copy is the right thing to do and it should be included in the final price tag. IMHO!