> I think people are often surprised how little materials cost affects the total cost of a job.

It's because they frankly never did it. Nobody that had to contract something around the house is surprised by cost like that, it often costs more than price of renting equipment + you doing it yourself 3 times slower than an expert would did it, even if you're paid well.

There is reason there is so many DIY channels, labour costs are high and install costs of some stuff can be ridiculous (like 2 hour job to install AC costing more than cheap AC unit).

That's also partly the reason the more expensive materials are used - if they offer savings in labour (say way faster to put in), they might be worth it vs paying someone for more hours

Yeah. I mean I just had some concrete slabs laid to put a bike shed on (literally bikeshedding, the colour is green, that's what it comes powdercoated in from the supplier, take it or leave it).

It was 300 quid.

I could not buy the materials for 300 quid.

Two guys showed up with eight slabs, half a tonne of Type 2 and half a tonne of sand, and then the next day the landscaper showed up and did about six hours of work to dig it all out, fill it all in, and put the slabs down.

It's absolutely perfect, exactly how I wanted it, and it would have taken me a couple of days and cost far more - and I'm quite good at that kind of stuff, it's just not what I do all day every day so the landscaper will be far better at it.