> But if I save a lot of memory/speed with it (session), I will have to live with it.

In reality unless you are planning to instantiate 100s of objects between pauses waiting for user input there is no practical difference between any of the classes ( OK I would stay away from using form, with of course the exception of using a form as a form )

Now I like session because it has it’s own datasession and I prefer that each object keep its own PEMS and Data separate from all others. When I do need to share I tend to use Relation or Line. I find Custom has too many PEMs out of the box.

Again thou if you want to use Custom or container etc. for the majority of your classes go ahead, I doubt even a very fast stopwatch is going to be able to show you any difference. As for memory unless you plan to instantiate 100s of objects and keep them instantiated I doubt you will have any memory problems. Worry about large arrays ( collections? ) Cursors, forms etc. first.

This of course IMO, but based on lots of actual experience thou.

Anthony