Heavily depends on the tool. There are a lot of youtube comparisons.

https://www.youtube.com/watch?v=bytkgeo9Q1g

There is still a ton of play in most the tools with moving parts. (AKA don't buy a drill press because there is a huge amount of play in the HF versions). The cheap home depot tools though are actually pretty good if you get the reasonable ones. AKA a good Ryobi 18V drill is just as good as the yellow or red ones that cost 2x-3x as much despite the "contractor grade".

https://www.youtube.com/watch?v=wTuiMcOXAwk

(there are a bunch of videos with people killing dewalt drills, batteries, etc. At least over the past few years their reputation doesn't appear to be deserved.)

Anecdotally cheaper brands of power tools seem to have a higher rate of return despite being mostly sold to consumers who are extremely likely to use tools in a less demanding fashion compared to contractors that who buy more expensive tools. This leads one to believe that the more expensive brands are better made and more durable and therefore worth the premium. If you time your purchases around frequent promotions you probably will pay less than 2x for the better quality tool and may well even save money in the long run.

Example if you pay 1.8x the cost for a tool that lasts 10 years vs 1x for 4 years of service you will actually have paid LESS not more.

One also notices that pro's tend to buy brand name tools rather than budget brands even when they are budget conscious in other ways.

Not if you're a professional mechanic intending to use it every day for 30 years. I believe that breakage resistance and level of wear and tear are not the same.

And if they're not identical, do you really need the quality of the more expensive one (supposing it is in fact higher?)

There are large differences in wrench quality. Cheap wrenches have poor tolerances in the heads leading to burred nuts. Also there can are superior designs in some ring spanners to reduce burring. Ok if you only want to use a nut a few times, but if it's a machine you want to be servicable it's very impotant to use decent quality tools.

Harbor Freight hand tools are surprisingly good these days.

I'd wager their wrenches are damn close to identical unless perhaps you're using a lengthy cheater.

(Machines more complex than a simple lever probably have more room to differentiate themselves.)

They aren't the same. At the very least, good wrenches are forged, shit ones are cast. Just for starters.

Harbor Freight sells lots of drop forged wrenches:

https://www.harborfreight.com/8-piece-sae-offset-box-wrench-...

I wouldn't buy their stuff if my job depended on my tools, but for something I need twice a year at my house, no problem.

My point was that you won't put enough force on either of them to discern a difference without a cheater bar. Maybe if it's a very small wrench.

I'd like to see you torque a 1" harbor freight wrench to the point of failure with your bare hands. I don't think you could do it even with your full body weight or something to push off of.

There are certainly cases where products differ enough in quality that there are pragmatic reasons to avoid some brands and prefer others. But I think standard wrenches are a poor example if you're trying to convey this point.

Sure. It's usually cheater bars that bend/break cast wrenches. Not common for around the house stuff, but very common for rusty bolts on cars, for a shade tree mechanic. Though the tolerances on cheap wrenches can certainly round off nuts even in around the house situations.