Some of Mr. David's office-coffee clients, who make up 75 per cent of his business, have started switching to single-serve machines to save money.

Warning: That free office coffee might be costing you your heart health. Here's all you need to know to avoid cardiovascular risk over time.

Note: This Dear Annie column originally ran in 2021. Dear Annie: I work in a small office with only four employees and one supervisor. Two of my colleagues and I are coffee drinkers.