As a follow-up to my question regarding the first-time installation, I noticed Steam stores the DirectX and vcredist etc files individually in each games directory. That means, those sometimes up to 100 MB are downloaded and stored over and over again wasting both space and downloading time.
Can Steam be prevented from re-downloading and duplicating game requirements like DirectX over and over again?
Best Answer
The problem has been discussed on the Steam Forums. The problem is that each game has to have a binary-identical version of the vc++ redistributables. Since games link against different versions of these libraries, steam always installs them the first time as a safeguard.
Credit to mordi2k for finding the post
Here's a link to the Steam Support Article about it (forum post is no longer available). The text is quoted below.