Confession time - I'm pretty compulsive when it comes to my cooktop. I can't stand to see it dirty and mine is white! Having a black one is almost worse because you can let it go longer and it is tougher to get the stains off if they are repeatedly cooled and heated.
I clean mine almost every time I use it because, even if I don't have a spill-over, often there is some discoloration because I have all calphalon cookware (a couple of mine are the original really heavy commercial pans from the mid 80;s).
I've had mine since 2004 and here's what I do. I keep a single edge blade widget in the drawer next to my stove and a big bottle of comet soft scrub (which I also use on my porcelain sink). If it's just a slight discoloration or spill, I just use the blade and some warm water - takes no time. If I've done my weekly cooking on Sat or Sun, I will take a little warm water in my sponge, squeeze it out on the burners (cool) and then squeeze a little soft scrub and rub it around with my fingers. While I'm doing something else like loading the dishwasher or something, I let it sit. Then I just go back with my sponge (I use the type that have the scrubber on one side) and then just wipe in circular motions. If there are any tougher stains, the blade takes them off.
Mine looks shiny and new all the time.
Sharon