T-SQL Get dates on a specific day when you don't care about time

Quite often I have to write queries to return rows where something happened on a specific day. But the values in the table could be anytime within that day.

Previous I would pass in a start date, end date to do this, but the query then needs 2 parameters and it looks a bit cumbersome.

I came across this method which I now employ. Don't know if this has much performance impact, but it certainly is quicker to code and takes less parameters from calling application.

Where
(
DateDiff(day, @ReportStartDate,TerminalSession.StartDate) = 0

--StartDate >= @ReportStartDate
--And
--EndDate >= @ReportEndDate
)