When blockages keep coming back

The line has blocked more than once, with normal use in between.

The single most useful thing you can do about a recurring blockage costs nothing: write down the dates. A shortening interval is information no camera can recover later.

What this page cannot establish

noticing this establishes that you noticed it — it does not establish a cause
this page cannot establish that recurrence proves structural damage
this page cannot establish that recurrence proves root intrusion
this page cannot establish that the line requires replacement rather than maintenance
this page cannot establish the location of whatever is causing the recurrence

What a professional will be trying to work out

These are the distinctions a professional makes when they attend. They are questions, not conclusions — and knowing them lets you follow the conversation rather than just receive its result.

the interval between events and whether it is shortening
whether the same fixtures are involved each time
what was done at each clearing and whether the method differed
whether the line has ever been inspected between events rather than only cleared

What is worth writing down

These details are cheap to record now and impossible to reconstruct later.

the date of each event you can recall or document
which fixtures were affected each time
what method was used to clear it, if you were told
whether the interval between events is getting shorter

Evidence that would change the next decision

If you are deciding whether something is worth paying for, these are the things that actually move the decision.

dates of each event, which is often the most useful single record
invoices showing what was done each time
a camera inspection performed after a clearing rather than before
whether anything was recovered or observed during clearing

What would change the answer

dates of each event, which is often the most useful single record
invoices showing what was done each time
a camera inspection performed after a clearing rather than before
whether anything was recovered or observed during clearing

What to do next

Recurrence is the classic case where an inspection performed *after* a clearing, rather than before, is what changes the decision.

Understand what an inspection after clearing would show

If your situation is different

You have been told it is roots: When a professional says roots
You are being quoted for replacement: Repair or replace: the questions that matter

Limits of cleaning
Repeated clearing produces very little information unless someone looks.
Project brief
The dates and invoices from each event are exactly what a brief is for.