The engineer on the line asked when it was last serviced and was a bit shocked to find it never had been.
"There's not often any major problem but it's as well to have someone check it out once a year or so, just to be on the safe side."
So a service engineer came out. He look at the kit and scratched his head.
"This stuff's self-servicing. You shouldn't need anyone to come out."
Seth explained what he'd been told and then pointed out some of the problems he's been having to deal with. That was at nine this morning. The engineer's only just re-emerged from the gubbins, having spent all day sorting out a problem that he reckons wouldn't have happened if it had been serviced properly.
The problem is that we've all worked here so long that this makes sense to us.