When you’re setting up your ad campaign it’s usually a mistake not to set it up with a schedule.
A schedule basically tells Google when to show your ads and when not to. The default setting will show your ad all the time day and night. For a lot of advertisers this is a good idea, but a lot of the time this is not a good idea.
If you’re company who relies a lot on taking phone calls and you don’t have people to take phone calls for you 24/7, then you’re not going to want to run your ads 24/7 because the people who come into your site late at night they may try to call you and when they can’t get a hold of you they’ll either move on to the next advertiser or they’ll forget about you. True there will be times when they leave a message or call back the next day, so you don’t necessarily want to completely eliminate the overnight hours (or whatever days or hours are considered your low peak hours) but you might want to adjust your bids.
You don’t necessarily want to completely turn your ads off at night. You will get some customers at night who call the next day and become a customer. But generally if your business isn’t set up to handle customers in the evening, you want to at least the lower your bids, and you can do this by a bid adjustment based on time of day. Or what I mainly recommend is actually setting up a different campaign. Just copy and paste your existing campaign, set one of them to the daytime normal hours, set the other one to the off-peak hours. The off-peak campaign is going to have reduced to bids so you still get some traffic but it will be a lower-cost meaning that even if the conversion rate is lower you can still be profitable.