Why fixed dates cost you money
The price for a route with fixed departure and return dates depends heavily on demand for exactly those two days. Shift either date by a few days and the price can move substantially, even for the same route and roughly the same time of year. We go into this in more detail in How to Find Cheap Flights You'd Actually Take - the short version is that date flexibility is one of the few genuinely reliable ways to lower what you pay, more reliable than which site you book through.
The gap in most "flexible date" tools
Google Flights and Kayak both offer a version of flexible-date searching - Google Flights' "Any dates" mode and Kayak's Flexible Dates tool will watch a window of time for you. What neither lets you do is constrain how long the trip itself should be. They'll surface the cheapest combination somewhere in your window, but that combination might be a 3-night trip when you wanted 10, or a 21-night trip when you can only take a week off work.
How milo's flexible-date alerts work
Set a date window - say, any time in June or July - and a trip-length range, say 7 to 12 nights, along with your route, cabin and target price. Milo scans across that window rather than a single fixed pair of dates, and only notifies you when a combination hits your target price at a trip length you'd actually take.
This is one half of what makes a flight price alert genuinely useful rather than a source of noise - the other half is a real target price, not just a lower number than before.
Frequently asked questions
What's the difference between "flexible dates" and a fixed alert?
A fixed alert watches one specific departure and return date. A flexible-date alert watches a whole range of possible dates and finds the best combination within it, which usually turns up better prices than committing to a single pair of dates upfront.
Can I set a minimum and maximum trip length?
Yes. You choose a range, like 7 to 12 nights, and milo only considers combinations that fall inside it.
Does milo check every date combination or just a sample?
Milo scans across your full date window rather than a single guess, so the price you're shown reflects a genuinely good option within the range you set, not an arbitrary one.