Stand at the range on an ordinary evening and listen. Turn a burner to light, press the knob, and count what you hear. A healthy igniter gives a short run of clicks or a glow, and the flame takes hold on the first try. When the clicking runs longer, or the burner needs a second press, the igniter is telling you something. Write it down before it turns into a habit you stop noticing.
What to watch for
Watch for a few patterns over several weeks. The first is the length of the clicking before ignition. If it grows, the igniter is losing strength. The second is a burner that lights only after you hold the knob longer than usual. The third is a flame that catches unevenly around the ring, or a burner that goes out when a pot is set down or a draft crosses the cooktop. Clicking that continues after the flame is already on is also worth noting, because the spark should stop once the gas is burning.
If your range uses a hot surface igniter, you will see a glowing element before the gas valve opens. A weak one glows slowly, dims, or glows only in one spot. Treat that glow as a reading, not a thing to touch. Keep hands and cloth away from it.
A smell of gas is a different matter
If you smell raw gas when you light a burner, stop. Do not try again. Turn the range off at the knobs, open a window, leave the room and the house, and call the gas utility or the emergency number for your area from outside. Do not use switches or appliances inside while you are unsure of the air. This is the one part of this walk-through that is not a planning matter.
Checks you can make yourself
With the range off and cool, lift the burner caps and wipe away spilled food and grease from the cap and the small electrode or igniter area beside it. Make sure each cap sits flat and centered, because a shifted cap can block the spark. Confirm each knob turns smoothly and returns to its off position. Let everything dry fully before you light anything again. These are the checks a homeowner can reasonably make.
Do not take the gas valve apart, and do not work on the wiring or the igniter's electrical connections. Those belong to a qualified technician.
What to ask before you book the call
When you call for service, ask whether the technician will test the igniter itself and the gas valve, and ask which one they suspect and why. Ask what part they expect to replace and whether the estimate lists the part and the labor separately. Read each line of the written estimate before you agree to it, and ask what it covers and what it leaves out. Compare the answers across more than one visit if the first fix does not hold.
Where this fits the plan
A slow igniter is often a single part, but it can also be the first sign that the range is nearing the end of its planning window. Find your range on the ranked list of the six major appliances, then set a planning date from the install year. If the range is near that date and the repair is one of several, weigh the repair against replacing the unit. Ask yourself whether the next few years of use justify the spend, and whether the other parts of the range are showing the same age.
The full ranking of the six major appliances is here: the six major appliances, ranked by typical service life. Use it as a planning input, and let the walk-through you did at the range tell you when to schedule the next look.