CAPTCHA's are very user unfriendly and often poorly designed, especially for those with accessibility needs (read everyone), so I only use them if there is no other alternative and it is absolutely necessary. I had to abandon a site yesterday because I couldn't "solve" the "simple" CAPTCHA after six tries, even when using the audio option. The fonts used on that one made determining uppercase from lowercase impossible and the audio just announced the letters without saying what case they were.

I'm sorry that the bad actors in the world make it harder for everyone else.