You don't have to weigh yourself each day if you don't want to lose weight and keep it off.
Weight watchers usually requires weekly weigh-ins. Isn't that enough?
Think of weight loss like driving a car without a gas gauge or a speedometer. You don't need a speedometer or gas gauge but they will help prevent you from speeding or running out of gas.
Weighing yourself each day is the same. You need to know what to do each day. Can you eat that piece of cake? Should you exercise. Knowing your weight in comparison to your daily goal will tell you exactly what to do. If you wait a week it may be too late.
On the Excel Diet you're trying to lose a pound a week. That breaks down to 1/7 of a pound per day.
Also knowing how much weight you can gain it one day is important when you've reached your goal weight and want to keep it off.
If you want to weigh below 160 lbs. and you've gained 4 pounds in one day, then while you're trying to keep the weight off you should be careful if you're above 156. As you could gain 4 pounds and be above your goal weight.
Weighing myself each day and modifying my diet and exercise is the reason I lost the weight and have kept it off. Have you lost weight and kept it off?
Maybe it's because you're not weighing yourself each day.