How Long Has This Been Failing: Decision Tree

Why this matters

"How long has this been going on" sounds like small talk. It is not. The answer decides whether a warranty covers it, whether a claim holds, whether the customer's story checks out, and whether the fix is a part swap or a bigger conversation about neglect. Guessing high or low both cost you. This tree walks you from the loosest evidence to the firmest so you land on a duration you can defend.

Start here: make it safe, then read it cold

Before you handle a failed component to inspect it, make it safe: de-energize and verify dead, relieve stored pressure, isolate water from any live part, and let hot parts cool. A dead unit is also easier and safer to read. Only then start dating it.

Now sort your evidence by how much you can trust it. Hard dates beat wear reads; wear reads beat the customer's memory. Work them in that order and stop when they agree.

Step 1: Is there a hard-dated record

• If yes - an install sticker, a service tag, a prior invoice, a date-stamped customer photo, a fault log with timestamps: start there. This is your anchor. But an install date only bounds the oldest the fault can be; it does not date the fault itself, so keep going to narrow the window.
• If no dated record exists: go to Step 2 and let the wear carry more weight.

Step 2: What do the wear clocks say

Read the physical clocks and place the fault in a bucket - recent (days to weeks), months, or long-standing (a year or more):

• Little to no accumulation (bare metal, bright fracture, thin film, no corrosion in the break): lean recent. Caveat: a sealed or oiled fault can stay bright longer than its age, so confirm with a second clue.
• Moderate buildup (even dust film, first flaky corrosion, brown heat color, a visible wear groove): lean months.
• Heavy buildup (packed dust, pitting or scale loss, deep blue-grey heat oxide, deep grooves or play, corrosion inside the fracture): lean long-standing.

Look for undisturbed markers too - insect nests, leaf litter, or unbroken dust bridging a connection all say the area has sat untouched for at least a season.

Step 3: Does the wear read agree with the record

• If the wear and the hard date agree (unit installed two years ago, wear says long-standing): you are done. State the bucket with confidence.
• If they conflict (service record says it was clean six months ago, wear says long-standing): the conflict is the finding. Either the earlier service missed it, the environment is unusually aggressive, or the record is wrong. Your defensible window is between the last known-good date and now. Say exactly that.

Step 4: Where does the customer's account fit

Bring in what the customer told you last, not first, because memory is the softest evidence.

• If it matches the physical read: note it as corroboration.
• If it conflicts (they say "it just started" but the evidence says months): do not argue. The evidence dates the fault; the customer dates when they noticed it, and those are two different things. A slow fault often runs unnoticed until it crosses a threshold they finally feel. See related: The Damage Is Older Than the Customer Claims (decision tree).

Step 5: Commit to a bracket, not a day

State the tightest range the evidence supports, tied to your firmest anchor:

• "Recent - within the last few weeks, based on the bright fracture and no corrosion."
• "At least a year - the scale and pitting could not build that fast in this water."
• "Between your last service and now - it was clean then, it is long-standing now."

Never assert a precision the evidence cannot back. A range you can defend is worth more than a date you cannot.

Recap

1. Make it safe before you handle it.
2. Find the hardest dated record and anchor to it.
3. Read the wear clocks into a bucket.
4. Reconcile wear against the record; the conflict is often the answer.
5. Fit the customer's account last, and separate "when it started" from "when they noticed."
6. State a defensible range, not a false-precise day.

References

• Trade-standard failure-analysis practice
• Manufacturer documentation on service life and wear limits
• See related: Reading Wear to Date When a Fault Started; Building a Forensic Timeline from Physical Evidence; The Customer Who Misremembers the History (decision tree)