One quick tip for getting the maximum value from your mail client's SPAM filter. Once you've got it configured or trained so that it's not getting many if any false positives, be sure to have it automatically file new SPAM messages in their own folder rather than leaving them tagged as SPAM, but sitting in your in-box. Then, periodically check the new messages in your SPAM folder to ensure that they're all SPAM by scanning the titles. Keeping the SPAM from ever getting in to your in-box folder will save you time because it's much quicker to scan a list of SPAM messages than to scan a list of messages that have SPAM and non-SPAM intermixed. You can quickly look down the list and then delete them all in one swat rather having to pause now and then to handle a legitimate email.
My SPAM volume has, sadly, increased somewhat lately, but it really doesn't affect me that much, because my email client files most of it automatically, and I'm able to process and it so quickly.