Buying a business is often faster and cheaper than building the same thing from nothing. You get customers who already pay, staff who already know the work, and revenue from the first week rather than the second year. For a business already operating well, acquiring a neighbouring one is frequently the cheapest growth available.

It is also the easiest way to spend a lot of money badly. Written criteria are what stop that, because they turn a market full of opportunities into a short list. Buyers without criteria look at everything, get attached to the first thing that is actually for sale, and talk themselves into it.

Know what you are buying for. More capacity, a new location, a skill you lack, a competitor removed, or a customer list. The answer changes everything below, and buying for a reason you have not named usually means buying for the wrong one.

Work out what you can actually fund before you look. A budget decided after you have fallen for something is not a budget.