Session Vars

I'm sure we've all heard the warnings about using cookies instead of session variables to store all of that user data so that our servers don't get bogged down. I'm just wondering how serious is this. I mean, is it just a suggestion or do these variables really take up a large amount of memory per visitor?

"Why would it matter? Just use cookies!" might be your response. Well, say I'm creating a user backend to edit a news section for a company. Now, I realize that the company newsletter is not mission critical information, but my novice-programming gut will not let me sit at ease if I store usernames and passwords in cookie data. What's to prevent someone else from looking at that local machine and fake my cookies, or even directly login with the information contained there-in?

For a recent backend along these lines, I stored a custom class in a session variable (all of you hardcore ASP guys can take a deep breath and stop twitching ). The class basically contained a copy of that user's database record (a user id, the username, the password, the e-mail address, and a few different permission variables).

I did this for two reasons:

1) I filtered all of my content through default.asp (meaning that each url looked something like default.asp?p=events where p was the real page request). Doing this allowed me to simply check the user's credentials in the default.asp script and then server.transfer them to the real page contained in the p querystring variable. I used the session-stored class after the first login (so I didn't have to hit the DB with each page request but could still make sure they had access to the site).

2) I knew before-hand that this system was only going to be used by 10-15 people max, and only 1 or 2 would be logged on at a time, let alone most of the idle time when no one was logged in (basically, it was a very low-load system so I didn't mind being unconventional). Code: