I have a number of hotel clients and if I've learnt anything over the years it's that hotels have 'fulfilment cycles'. They're not always the same but let's consider the fictional hotel 'The Outlook' (with apologies and necessary credits to Stephen King).
The Outlook consistently fills it's rooms on a Friday and Saturday night and, for all intents and purposes has no need to advertise these rooms. Sunday, Monday, Wednesday and Thursday they do 'OK' and don't believe there's any benefit in terms of ROI (Return on Investment) in trying to get an extra room or two. But Tuesday is always terrible. Any time of the year, Tuesday night sees the hotel only half full at best, so there's a clear opportunity to fill those beds.
So how can Adwords help for just one day a week?
The 'knee-jerk' response is, of course, to use Ad Scheduling to show the ads for The Outlook only on certain days of the week but with a hotel this can't work. Someone looking for a hotel room on a particular night may search for it on any given day before that night, not necessarily the night in question. Limiting the ad display to just - say - Monday will not catch those who were trying to book a Tuesday stay on the Friday before*. So, what can you do?
The key to success here lies not so much in the Adwords features but in what and how you advertise. If you create ads that simply promote the hotel then you'll get clicks looking for any random (possibly booked) nights of the week. What you need to do is promote Tuesday as the night to stay. So, your ad copy needs to mention Tuesday night. But why should I stay on a Tuesday? This is where the hotel needs to be pro-active in encouraging customers. If you want beds filled on a Tuesday then you have to make Tuesday night more attractive than Monday. So your ads need to include an incentive - a strong 'call to action'. Offer a free breakfast, 10% off, or a double room for the price of a single only for Tuesday nights.
What each hotel (or other business) can offer here depends on the business but there's usually something that can be offered at limited outlay but which seems appealing to potential customers.
So, you can run your ads all week but because your ads are clearly offering a Tuesday night special, you can reduce the number of 'wasted' clicks from customers who are not staying that night.
*That said, with some effort and time, it might be possible to establish a pattern. IF your hotel site gathers proper data and is able to analyse it effectively, it may be that you can tell which 'advertising days' are linked to which 'stay days'. However, there's no guarantee that such a correlation will be found.
So, in short, it is possible to use Adwords to fill those 'gaps' in the schedule, but success here is more related to ad copy and offered services/discounts than anything Adwords can do as a setting or feature.