It is a lot common that people who are using Adwords or Bing ads or even Yahoo Gemini for their business tend to forget updating the ad scheduling for their campaigns time to time. It is very important for businesses to analyse that on what day and what part of the day their audience tend to buy or engage with their website the most.
It depends, the ad scheduling for different businesses cannot be the same. Suppose if I were a digital marketing agency, just because my audiences would be either some executives or employees of other businesses seeking out for digital marketing agency, I would avoid advertising on the weekends and rather spend more on week days, so that my ads show up most of the time. Even If I would look at the day parting I would see that the major traffic would be between 9 am to 5 pm. Or if you are an online grocery store, your website traffic could be high at the starting of the week, a Sunday or Monday, just when the house owners think that they need to replenish their grocery stock again for the week.
These are just examples but what every digital marketer could do is check on what days and what part of the day the traffic on their website is high. Ad scheduling can help you distribute your budget into profitable parts of the day.
So, start your week with some research on hour of the day. Know when your sales are high. Create a a perfect ad scheduling plan for your business.