You're breaking your back carrying water that you already have in your washing machine.
You're lugging these heavy containers up stairs, down to the basement, or across the house just to do a basic load of laundry.
At our age, we shouldn't be risking a fall or throwing out our back for what's essentially water with a little detergent mixed in.
My 68-year-old neighbor Janet learned this the hard way. She was carrying a full jug of liquid detergent down to her basement laundry room when she missed a step. Twisted her ankle, bruised her hip, and couldn't do laundry for three weeks.
All for a bottle that's mostly water anyway.