wixUser ID for Guest

Hi Guys

Cheers in advance for the responses.
I understand the wixUser.id is a unique value assigned to members and remains with the member for life. However with guests once assigned, Can that ID be allocated elsewhere once the user leaves the site?

Basically
User A (Guest) enters site, gets assigned an ID, i use that ID for UX
Can User A’s ID ever be given to another user or is it jsut a thing of the past when that user leaves?

Hope this makes sense, it did in my head but unsure about on a post.

Cheers

You can assume user id is unique per user and is not being reused.