Our homeschool lessons are determined by time rather than page count, which means that for most subjects we stop when the timer goes off and move on to the next thing on our list. Our visual timer (we have the 8×8 one) has been a wonderful tool for both myself and the kids. I love that it keeps me on track and helps us keep our lessons short, and the kids love being able to see how much time is left in each subject. This one tends to be pricey (I paid around $25 for mine) but I have found them to be very durable. We have had ours for several years!