[FX.php List] Shopping Carts - Keep in SessionVars or Add Records right away?

[Joel Shapiro]

Hi all

Anybody have any thoughts on *when* in shopping cart functionality  
it's best to add items as records to the database?

My initial thinking is that it would make more sense to just keep  
items in Session Variable arrays and only add anything to the  
database at the time of Checkout -- to keep the DB from bulking up  
with unpurchased items left in the cart.  But searching online, it  
seems that carts often add records to the database as soon as they go  
into the cart.  (Might that be different when using MySQL as opposed  
to FMP?)

FWIW - Users on this site will average 1-4 items per order.

Whaddy'all think?

TIA,
-Joel