A replacement proposal usually names one company and one price. On install day, the people who show up are the ones who do the work, and they may not match the name on the paper. A two-person crew can include a licensed technician, a journeyman, and an apprentice who is still logging hours. None of that is unusual. What matters is whether you know who is doing which task and who is accountable for the result.
The trade is working hard to bring in new people. ACHR News reported on SMART Sheet Metal Workers Local Union 49's new training center in Lubbock, which is "already drawing strong interest" while expanding apprenticeship opportunities for contractors in the area. That is good for the trade. For a homeowner, a growing pipeline means more mixed crews on more jobs, so the questions you ask before the first panel comes off need to be specific.
Get the names in writing
Before you sign, ask the company to put three things in the contract or a follow-up email: the name of the licensed person responsible for the job, the name of the lead technician on site, and whether any apprentices will be working on your system. Most reputable shops can answer this in a sentence. If the answer is vague, treat that as information.
Then check the credentials yourself. Most states and many cities let you look up a license number on the licensing board's public site. Confirm that the license is active and that the company name on the license matches the company on your contract. Rules on apprentice supervision, permit pulling, and who must be on site vary by state and by city, so look up the rule where you live rather than assuming how it works elsewhere.
Know what the licensed person owns
An apprentice can handle a lot of the physical work under supervision: pulling old equipment, running line sets, mounting the air handler, making up connections. The tasks that set the final performance of the system are the ones to watch. Refrigerant charge, airflow, and the startup checks belong to someone who can explain the numbers and stand behind them. Ask who will perform those checks and who will record them.
Ask, too, who will be present at the end of the day. A good handoff includes a walk through the thermostat, a plain explanation of the disconnect location, and a clear statement of who to call if something is off. If the person who did the work is not the person who explains it, ask to speak with the licensed lead before the crew leaves.
Measure what you can
You do not need to second-guess the technician's craft to protect yourself. You only need a multimeter and a clamp meter, and the willingness to write numbers down. Before the crew starts, take a reading of the supply voltage at the outdoor disconnect and note it. Once the new outdoor unit is running, clamp the compressor leg and compare the measured amp draw with the rated load amps on the nameplate. A large gap in either direction is worth a question.
Ask for the same information in writing from the crew. Good records include the readings they took, the supply voltage they observed, and the temperature difference across the indoor coil at startup. If the numbers they give you do not appear anywhere on paper, or they cannot tell you how they measured them, you have learned something useful before the warranty clock starts.
Keep the paper that names the crew
Once the job is done, file the contract, the license number, the names of everyone who worked on the system, and any startup readings together. If a problem shows up in six months, you will know who did the work and who was responsible for it. That record also protects the apprentice, who is learning in public and deserves a clear chain of supervision.
The goal is not to keep new people out of the trade. The goal is to make sure every person on your roof, in your attic, or at your air handler is doing work they are qualified for, under someone who answers for it. Ask the name, check the license, measure what you can, and get the handoff in writing.