.. The big box retailers have done damage to professionals by convincing home owners they can do it themselves. ..
I think you have this backwards.
TLDR:
- the quality of an "average" contractor is plain atrocious these days, any trades "honor" that existed in past is long gone
- the economy in the West /US, Europe is worse/ is going down the drain for the middle class for decades, this makes contracting-out plain unaffordable especially for the younger people
These two combined
force people into the DIY space. Both the low end of it and the above-professional end of it /represented in the FOG crowd/.
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Finding someone doing the job properly requires you /the customer/
to know how to do the job so you can watch over them and ensure they do not skip steps etc. If you are rich, you can have the good guys selected, but the middle class cannot afford to pay up a premium "general contractor" to take care of that. Premium meaning 2x to 3x of what a direct bid lands /talking of Central Europe now, but presume this is universal, good work is not cheap/. *)
This results in people who are capable to not see the benefit in paying good dough for work that is *worse* than what they can do even without the skills. Meaning. If I have the time, I would rather do it myself at material costs and mess it up BUT be able to fix it up than pay someone to mess it up for me ..
Yes. That is how I got into electrical wiring when 16 .. I got shocked after an electrician "repaired" sockets in our apartment in such a wonderful way there was 230V AC at the grounding pins on some wall sockets. No. Not joking. Or into gas appliances after our water heater got "repaired" in such a way there was obvious flame leaking sideways from the burner. The gasket was mis-aligned. Again. No joking matter. Since then I install/repair gas appliances myself and have a technician come to check for leaks/issues. I am fine with him taking it apart and back together in front of me, but would never let it be done on trust. Call me paranoid all you want.
Then. A huge, huge, argument for DYI is clean-up costs.
It is no good I saved a workday or two by not doing the work .. if the consequence is my SO spending a week in clean-up after the contractor instead. Dust and stains everywhere. If that SO is working and not at home with kids - common today - the "savings" math suddenly stops computing. It becomes economically viable even for a relatively high-earner.
Lastly. I earn my living by my brain. Doing manual work - even not simple work - is relaxation for someone with an office job. This changes a calculus greatly from the past when most people worked manual jobs of one type or other and were physically tired to pull "another shift" at home. I am dead on Friday still. But psychically only, my body plain screaming for physical activity .. I know this is hard to imagine for trades folks but is a big reason high-stress job people like doctors, IT people, lawyers, etc. are into DYI. It is a stress relief opportunity.
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*) This is how I got into woodworking. I came to realize than to have quality furniture and other stuff made I HAD TO learn how to make it well to even be able to contract it out properly. But then, once you know how it needs to be made .. there is very little reason to not to do it yourself .. as you quickly learn that those who *can* do it properly are really, like really expensive and hard to book to begin. Yes, I got into a "hobby" by economic necessity - it was plain unaffordable to get
quality custom stuff made to order and I do not need to be a rocket scientist to "adjust" IKEA furniture once I got the tracksaw-router-sander basics sorted out. And do not get me started on painters. A friend had an apartment painted "professionally". They are now saving up for a complete renovation as a result as *all* the pain will have to be scraped and all walls re-plastered /brick walls/ as wrong, non-breathing, paint was used on the walls. Yes, they were lied to by the uneducated contractor that the paint is "breathing" based on him reading it on the can and not understanding that "breathing" and "breathing" are not the same between paints. Now they got mould all over the place on the outer walls as the paint closed those up..