Help them help you
I'd moved furniture, removed the dust and spiders so that when the engineer turned up...
Straight in and out.
Less than 20mins later; new cable run, new box, new router, FTTC installed tested working.
He mentioned this was an easy job, sometimes he's climbing over furniture, under beds, got knows what.
If we could all try a little to make it easier, they'd probably be late less often.