I used to delete spam from my Akismet net every chance I got. Then it started to flood my Wordpress site, and I found that even if I checked every minute, I'd still find spam there. So I gave up on having an empty spam catcher, and decided to let the 15-day expiry rule work and delete them for me.
Now I find that it's reached an equilibrium of around 1000 spam comments; as more spam comes in, the old ones are deleted at roughly the same rate.
What's your spam equilibrium?

10 Comments
JoeLencioni
Written Oct. 19, 2007 / Report /
Mine's at about 300, but I also use Bad Behavior which cuts down on spam quite a bit.
publicenergy
Written Oct. 19, 2007 / Report /
Odd, I use Bad Behaviour as well, but mine is 1500! - Who knows how these things work! hehe
Josh
Written Oct. 19, 2007 / Report /
I'm not sure what mine is; I still manually delete the spam every few days. I know I deleted them all a few days ago, and I just checked, and I had around 800.
I also saw that Akismet has nabbed about 25K spam comments for me so far. (!)
Ozone42
Written Oct. 19, 2007 / Report /
So far this week I've had 600.
Spambots love me. You'd think they wouldn't bother when none of their comments ever surface.
dreamweaver
Written Oct. 19, 2007 / Report /
Mine is around 7-10. Don't know why it's so low, but it's probably a traffic issue. :(
hthth
Written Oct. 19, 2007 / Report /
I manually delete mine which are around 10-20 per day, few enough to manage. With Google still upset with me after I switched domains it seems the spambots are having a harder time finding me. I recently got two days of no spam, which kind of freaked me out.
publicenergy
Written Oct. 19, 2007 / Report /
Is there any reason people delete them rather than just let them delete themselves after the 15 days?
estarla
Written Oct. 19, 2007 / Report /
I was clearing them out about twice a week (about 50 each time) w/o even scanning through them but then I was notified by a few commenters that their comments had disappeared and had probably been marked as spam. So now I at least look through them...
chapstick
Written Oct. 19, 2007 / Report /
I manually clear out my spam comments about once every other day. After about two days, I have around 20-30 spam comments.
I don't have my cms auto delete the spam comments after a few days because I still don't trust that all my spam comments are spam. I don't know why, but I always feel like I have to check them out first to make sure it's not a legitimate comment that Akismet marked as spam.
The same goes with e-mail spam.
superrats
Written Oct. 19, 2007 / Report /
Every now and then I'll just empty the bin. Last time I did it was ten days ago and I've got 1048 in the bin. I don't check for false positives anymore.