Adding extra fields to user table

[ravenswood1000]

Is it ok to add some extra fields to the user table or will I regret this later (expecially if we upgrade to vbulletin5)?

Parts of our website use vbulletin for authentication and we would like to keep track of some other bits of data which would seem logical to keep with the vbulletin user data but I don't want to do something that we may regret later. We currently use vbulletin 4.

Thanks much for any advice.