True story · retold with care
Kara Goldin lost 40% of her revenue in one phone call
Hint had earned its way into Starbucks, and by 2012 that single account was roughly 40% of the business. Then Starbucks rang. Food was going into the stores, Hint was coming out of the fridges, and the notice was about two weeks.
Kara Goldin describes it in Undaunted as being punched in the gut. Hint came through it by building a channel of its own, helped along by an Amazon buyer who had first tried the drink in a Starbucks.
What went wrong
A client who pays a large share of your bills is not a strength, it is a single point of failure. The decision that ends the relationship gets made in someone else's meeting room, on their timetable.
The habit that prevents it
Know what share of your income each client represents, and treat anything near a third as a risk to manage rather than a relationship to celebrate.
How you'd see this coming in Punctual
Punctual shows revenue and real profit per client as they stand, so one client quietly becoming most of your business is a number you watch, not a fact you learn afterwards.