Updates & Disk Space

Software updates (for example, the ones that frequently show up in the lower right notifications area in Windows 7, like Java, Adobe, etc.) take up some space on your hard drive. Very small I'm aware, and sometimes they tell you beforehand how much space it requires, like some MB's for example.

My question is, generally (most of the time) these updates not only install new files but also REPLACE existing ones? Since that would make sense...otherwise you'll hard drive space will just gradually decrease and decrease with time...

At least the Adobe one I ran few minutes ago had "deleting old files" and "copying new files" at some point in its status...

Thanks, and sorry if it's an easy question but I'm not sure if all of them are like how Adobe do it.

Generally most software updates overwrite the existing files they're updating. Some driver updates do not, such as AMD Radeon updates. However, one may go to the ATI folder in C drive and delete the older driver folder with no problems. I do this whenever I update to the latest Radeon drivers.