Software update apple: lessen my hardrive space

I found many times through software update the unimportant software
update. For example iTunes. Today this update take almost 100 MB of my
HDD space without any differences with the previous iTunes. I don't
have any iTunes account, so, this update is not important for me. I
thinking for long time to update my iTunes or not and finally I
decided to update my iTunes. I afraid if I don't do the update, once I
find important update, I will find difficulty to update that version
since I did not update last version and the display will show to me
"this update can not install to your computer, please install the
previous version".