Calculated column to classify customers by spending

pb202134,

Your calculated column was missing ALLEXCEPT. Also, I replaced the IF statements with SWITCH (simpler). Try this:

New or existing to EP = 
VAR sales2019 =
    CALCULATE (
        [Sales from EP],
        'Summary EP orders'[Vintage] = 2019,
        ALLEXCEPT ( 'Summary EP orders', 'Summary EP orders'[Account] )
    )
VAR sales2020 =
    CALCULATE (
        [Sales from EP],
        'Summary EP orders'[Vintage] = 2020,
        ALLEXCEPT ( 'Summary EP orders', 'Summary EP orders'[Account] )
    )
RETURN
    SWITCH (
        TRUE (),
        sales2019 > 0
            && sales2020 > 0, "both vintages",
        sales2019 = 0
            && sales2020 > 0, "first time in vintage 20",
        sales2019 > 0
            && sales2020 = 0, " vintage 19, not in 20",
        "never bought"
    )