So many other devices come with timers, it's often enough to use those. That said, I can see the benefit of having a three-way timer when you're cooking a big meal. Just last night I used one timer for both the vidalia onion on the grill and the rice by putting the onion on the grill when I set the timer for the rice. 25 minutes of rice's cooking and 5 for it's resting gave me the 30 minutes I needed for the onion.
I was on my own for the fish.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan