It didn't exist in the late 60s. I was perfectly happy to pull out repair manuals. I was competent at electrical wiring by age 10. Satisfactory in natural gas plumbing and soldering copper pipes to replace a water heater. Youtube would have been nice, but you use what you have. I rode my bicycle 15 miles to an HVAC shop to purchase a replacement gas valve for my home furnace. The cheap fix with a new thermocouple didn't resolve the problem. It was a failed valve. The replacement was OEM spec and did the job. It was nice to have heat again in the house.
“It didn’t exist in the late 60s.”
Right. That’s why I said you probably wish it did. :)
“I was perfectly happy to pull out repair manuals.”
That’s me. I’d much rather READ a manual than watch a video. My brain learns better that way.