The refrigerator is not making a sound you can ignore, but it is making more of the sound it already makes. The compressor runs, stops, and runs again. Over time the gaps between cycles may shrink. That change is easy to miss because each single cycle looks normal.
What the change usually looks like
The cabinet stays on longer between rests. The room around it feels warmer than it did in earlier walk-throughs. The door may need a firmer push to close, or it may stay ajar a little longer after you let go. The food inside may feel less cold near the door than it did before. Each of these can have several causes, so treat them as a starting list, not a diagnosis.
Keep the log
On each walk-through, write the day, then four plain notes. Is the cabinet quiet between cycles? Does the run feel longer than your last note? Is the room warmer than usual? Does the door close firmly on its own? Keep the words plain, such as warm, cool, longer, or the same. The value of the log is the trend across visits, not any single reading.
Check what is yours to check
You can look at the area behind or beneath the cabinet and see whether the coils are covered in dust or lint. Clearing them is a household task. You can also confirm that nothing is pressed against the cabinet and blocking the air path. Do not open the sealed refrigerant side or work on electrical parts. That work belongs to a qualified technician.
What to ask the technician
Bring your log and ask whether the change points more toward a coil, a fan, or a control. Ask what they would check first and what they would expect to find if the cause is simple. Ask whether the repair would be worth the effort given the age of the cabinet. Keep the answer with the log so the next visit starts from the same record.