As a Flow community contributor, I regularly assist Flow users with the creation of their Flows. The great thing about a community like the one you can find at this link is that when I need assistance with an expression, an Odata filter or the use of a connector, help is never too far way. You just can't beat support like that when working with technology.
One of the common queries that comes up relates to the use of dates in a Flow. Dates and times are an essential part of application building, business processes and day to day life so we may have to say something like the following.
If due date is next 7 days do X, If not do Y.
If current date is 2 days before user 1's birthday (taken from a SharePoint List perhaps) send me a reminder so I can get them a present.
Get all tasks for the next 14 days from a SharePoint List and send a Monday email with these tasks.
The above examples, are merely just a snippet of some of what comes up relating to the format of the date or the expression required to match a date requirement.
But what methods are suitable to test these scenarios if it's just not working is not working for you?