Smart Bidding sounds like the easy win, but for most UK trade businesses it's a trap. Here is how to decide which strategy actually delivers.
Google's Smart Bidding promises to do the heavy lifting for you, using machine learning to adjust bids in real time across dozens of signals. For large accounts with thousands of conversions a month, it works brilliantly. For the typical UK service business spending between £500 and £3,000 per month, the reality is more complicated.
Smart Bidding strategies like Target CPA and Target ROAS require a minimum volume of conversion data to operate effectively. Google's own guidance suggests at least 30 to 50 conversions per month in the past 30 days. If your campaign is generating 10 or 15 phone call leads, the algorithm simply does not have enough data to learn. The result is erratic bidding, unpredictable costs, and missed opportunities during your busiest periods.
Manual CPC bidding, often dismissed as old-fashioned, gives you precise control over what you spend per click on each keyword. For a heating engineer running a tight budget, that control is invaluable. You can push spend on 'emergency boiler repair' on a cold Monday morning and pull back on less urgent terms when your diary is already full.
The right time to graduate to Smart Bidding is when your campaign consistently generates 40 or more tracked conversions per month. At that point, start with Maximise Conversions to let the algorithm learn, then shift to Target CPA once you have a stable cost per lead baseline. Rushing this transition before the data is ready is one of the most expensive mistakes a growing trade business can make.