Streaks!

Greg_Deckler, here's my simplification that should work at both the project and sub-project level:

Max Streak = 
VAR _MinDate = MIN ( 'Table'[Start date] )
VAR _MaxDate = MAX ( 'Table'[Start date] )
VAR _DateRange_ = CALENDAR ( _MinDate - 1, _MaxDate )
VAR _GapDates_ =
    ADDCOLUMNS (
        _DateRange_,
        "@IsGapDay", ISEMPTY ( FILTER ( 'Table', 'Table'[Start date] = [Date] ) )
    )
VAR _AddStreakIndex_ =
    ADDCOLUMNS (
        _GapDates_,
        "@StreakIndex",
            VAR _RowDate = [Date]
            VAR _LastGapDay =
                MAXX (
                    FILTER ( _GapDates_, [@IsGapDay] && [Date] <= _RowDate ),
                    [Date]
                )
            VAR _Index = INT ( _RowDate - _LastGapDay )
            RETURN
                _Index
    )
VAR _MaxIndex = MAXX ( _AddStreakIndex_, [@StreakIndex] )
RETURN
    _MaxIndex