My son aged 9 has Aspergers and finds timing difficult. We tried egg-timers but he forgets to look at them or doesn't notice when they've run out. The local Autism group suggested the Time Tracker. All I can say is Wow!! This has exceeded all my expectations. It's really helped him with so many things. EG If he's playing his DS before school, he knows he has to save the game once its gone yellow, but can keep playing till the light changes to red, then has to get his shoes on before the buzzer goes off. Similarly for something he doesn't want to do, e.g. homework, he can see once it gets to yellow he hasn't got too much longer to go. It provides a clear visual indication that he can relate to, as it's like traffic lights! This is something that words alone, clock faces, digital displays or sand timers don't seem able to provide for him. It's big enough and bright enough to catch his attention and there is always the option of a sound to accompany the change from green/yellow or yellow/red. We now use it for everything from making sure he brushes his teeth long enough to how much time he's allowed on the computer, to getting dressed for school. In fact all the family use it...we may need to buy more!
The kids love the different range of sounds and although programming it is not particularly intuitive once you know how to do it it is actually quick and easy. If I could suggest one thing to the company it would be to make a mini version that you can sit on top of a PC or on their desk (about 10cm tall would be great) not to replace this one but just to allow it to fit onto small spaces. Especially if you could program a small one with a specific time then just hit one button to start it.