Why not though Elfyn?
With the utmost respect to the more senior members of our profession, they originate from the days where a single 2-stage vac and 50psi pump was the norm. Things change, boundaries are re-defined, new technology changes the playing field.
In their earlier years they were probably challenging the old guard from a previous generation as to what products/systems were the best. "shampooing" was the method du jour, whilst HWE was the ground-breaking method some decades ago. If it wasn't for progression and innovation we'd all still be riding around on a horse & cart, living in mud huts........
The heat argument is one that will rage on forever. Likewise the pre-vac argument.
We all do it differently, and I know what I prefer, so each to his own. Just because someone who's been cleaning carpets 30+ years says "oooh you shouldn't do that" doesn't mean they're right and you're wrong (and vice versa of course). It just means they don't think the same
