My avast folder is 63MB, because I have quite a few skins that I downloaded, but in the scheme of things even 63MB is small, even on my 10GB HDD.
So unless you are really strapped for space, it hardly warrants the hassle and if so there are other more gready targets, such as system restore, unless you keep it in check it will grow to enormous size, 500MB is small I have heard of 1GB System Volume Information folders.
You can keep this in check using the disk cleanup -