You are probably paying for more than one thing right now. Lettering on the truck. A yard sign you leave behind after a job. A boosted post. Search ads. The sponsored page in the youth baseball program because the coach asked. Maybe a mailer in the spring.
Here is the test. Without looking anything up, name the ad that produced the last five jobs you ran. If you can't, you are not unusual, and you are also not in a position to cut anything. That is the real cost of not measuring: not wasted money, but the fact that you can't tell which money is wasted, so you keep paying for all of it.
You do not need software to fix this. You need a question, a tally sheet, and eight weeks of patience.
Clicks are not customers
Every ad platform will show you impressions, clicks, and a cost per click. None of that tells you whether a truck went to a driveway. A search ad can pull a hundred clicks from people comparing prices in a town you don't serve. A yard sign can produce three clicks total and two booked jobs, because the only people who see it already live on that street.
The only number that matters to a shop with two trucks is booked jobs by source, and the only place that number lives is in the conversation you have with the caller.
Ask the question in the middle of the call, not at the end
Most shops that ask "how did you hear about us" ask it last, right before goodbye. By then the caller has what they wanted and is already halfway off the phone. You get "uh, online" or a dial tone.
Ask that question after the appointment is on the calendar but before you read the details back. Once the caller has a time slot, the pressure is off and they will talk. But the call isn't over, because they still want to hear the day and time, so they stay on the line to answer. That one move in the order of the call is worth more than any clever wording.
Do the same thing at your desk. Book it, then ask, then confirm.
"Google" is four different things
When somebody says "I found you on Google," you have learned almost nothing. That could mean your map listing, a paid ad, a page on your website, or a directory that ranks above you and lists your number.
One follow-up question sorts it out: "Do you remember if it was the map with the pin, or one of the ads at the top?" Most people remember. Write down whichever one they say, and if they truly don't know, write "Google, unsure" and move on. Three months of "unsure" tallies is still a useful number, because it tells you the size of your blind spot.
Same problem with "a friend told me." Ask who. Referrals are the cheapest lead any trade shop gets, and knowing which five customers send you work is worth more than any ad budget.
Give each ad its own tell
The cheapest tracking in the world is different wording on each thing you pay for.
Put "ask about the driveway inspection" on the yard sign and nowhere else. Put a different phrase on the door hanger. Give the mailer a page on your own site, something like yourshop.com/spring, and print that on nothing else. When somebody says the phrase or lands on that page, you know exactly where they came from, and it cost you nothing but a line of copy.
This works across trades. A painter can put a different offer line on the estimate leave-behind than on the yard sign. An auto shop can use one phrase on the oil change reminder card and another on the radio spot. A pool service can word the April postcard differently than the website. A barber can hand out a card with a phrase on the back and see how many come back holding it.
Count jobs and dollars, not calls, using your own books
At the end of the month, pull two things you already have. What you spent on each channel, and what you invoiced on jobs tagged to each channel.
Spend divided by booked jobs gives you a cost per job for that channel. Compare it to your own average ticket, which you can get out of your invoicing by adding up last month's completed jobs and dividing by the count. Now you can see which channel produces work that pays for itself and which one produces tire kickers.
One warning. Do not judge a channel on one slow week, and do not judge it during a season swing. Garage door calls spike on the first cold snap. Pool phones light up in April whether you advertise or not. Electricians hear about panel upgrades when somebody buys a hot tub. If you change ad spend the same week the weather changes, you will credit the wrong thing.
Turn one thing off for two weeks
The hardest channel to measure is the one people see and don't mention, like truck lettering or the sign at the ballfield. The cheap version of a test is to pause one paid channel for two weeks and watch your call count and booked jobs. Then turn it back on and watch again. If nothing moves either way, you have your answer.
Pause one thing at a time. Two at once tells you nothing.
The words your callers use are the words to buy
Every trade has its own vocabulary. Garage door callers say the spring broke or it won't go up. Pool callers in the spring say the water went green. Auto repair gets the check engine light. Plumbing gets no hot water and a running toilet. Cleaning gets move out.
Write down the exact phrases your callers use for two weeks. Those phrases belong in your ad copy and in your search keywords, because they are what people actually type and say. Copy written in contractor language, like "comprehensive residential solutions," matches nothing anybody ever says out loud.
None of this works if the phone goes to voicemail while you are under a sink, because a caller who leaves no message leaves no source either (here is how to work out what your missed calls cost). Whoever answers your phone, whether that is you, a helper or a service, needs to ask the source question every time, in the spot where people actually answer it.