Thank you for the advise Gail ;
Just a few queries when you say high florescent or incandescent lighting do you go for Florescent, Incandescent WB respectively and what do you use for sports scenario you mentioned.
I pick the setting that matches the lighting; and check on the LCD screen as you can actually see the color changes as you use different white balance settings.
As to mixed lighting, such as at some sports events, I'd use a custom white balance. Saying this, if you edit, most photo editing programs do quite a good job at correcting white balance with a few clicks of your mouse.
btw, you've asked some very good questions in all your posts!