CSS Sprites

I'm not a stranger to sprites but I primarily limit my usage of them. I don't toss every image into a sprite. I tend to just stick with navigation majority of the time although very rarely have I had a project that required extras.

I used to do headings but after Cufon/@font-face came to play I no longer do that.

• How often do you use sprites?
• Do you use them for EVERY image (backgrounds included but excluding those you need to repeat)?
• Or just a few here and there?
• Does it really make THAT big of a difference when it comes to shaving off some load time?

I've got a client right now that wants to have ALL non-repeating images put into a single sprite. Truthfully, it's a huge pain in the ass right now as the site is already fully developed.. So I'm having to ensure that a.) I'm grabbing all images, b.) the code isn't going to conflict with the already existing styles. And I really just don't see the point in having 60+ images in a single sprite file... but I've never been one that used that many images in the first place ;\.