Is it possible to make multisession with any of the DVD formats, DVD-R, DVD-RW, DVD+R, DVD+RW, DVD-RAM? If so, which ones allow multisession recording?
( only yesterday I burned my very first video on a DVD+RW, and on lookling I found that some buttons on the menu didn't work properly and I decided to erase and rewrite. There was no possibility of a multisession, and I do not know if this is because of the medium being a RW, or because of the software I used, which once was DVD architect, the second time Nero Express; which does not seem to offer multisession, though I remember I used that a lot when writing CDs, but that could have been a different version of Nero )

Audo and video discs (whether CD or DVD) do not allow for multi-session
recording (this has some technical reasons). However, a RW or RAM disc
can be erased and used again. So if your DVD player(s) can read RW+- or
RAM then by all means use that.

You can use multi-session on a CD/DVD **DATA** disc, which is of no use
if you are doing video work unless you want to burn data files (or backups
of your original AVI/QuickTime files).

Nero (Express) does offer multi-session, but as explained only for data discs.
(as does any other burning software).

I hope that clears some things up.

p.s. also think about it, how could an extra session incorporate with the
first. Which menu should it play for example? That's one of the reasons
multi-session doesn't exist (another is that the DVD-video spec doesn't
support it, so wouldn't be compatible with any player)

you are right, thinking about it I should have known. Thank you very much for the clarification.
That means that now I must learn how to insert new menus, create a menu one level up etc. in DVDA, but I guess that won"t be difficult.

DVDA is SO easy! All you have to do to get started is to drag and drop your media files on an empty menu. DVDA will automatically create button link to your media.