The answer is none in my opinion. Just like everything in life, depending on how often you use something, how you treat it does play a role. That doesn't mean a person using something once in a while will have a better experience or wear as well as lifetime on a product, than the next person, that might use it in a complete different way or environment.
My grandparents are going by that myth too tho, and its understandable, everyone is looking or wants something that lasts the next 100 years and survives/outlives a natural disaster. Sadly, while that might have been the truth back in 1950 and products built to last, nowadays and especially when manufactured or designed in China, the life span of products have been extremely decreased. Now I'm not hating on China or whatever country but in most cases, even here in the US, norms are different and not everything would pass quality control or standard here vs other regions and vice versa.
So with that in mind one company you should not buy anything from is smok, do as you please of course, but most of their products won't last 3 months. Sure some have better luck, but I say luck because with that company its not like others, were you could blame it on bad batch. Its more like one person out of a million receives that one special and great working device lol.
Mods that are known for lasting longer than that are, Siegelei, most if not all dna chipset devices used by different manufacturers, voopoo, GeekVape, innokin, vaporesso, vandy vape, wismec, eleaf etc. That list is long.....
Sure some might work better than others but I mean that's expected otherwise we could all just buy the same. You should ask yourself what are you looking for? Then decide what features it should have, should it be portable, do you might have a labor intensive job were the mod could fall of a roof or into water etc., do you like to use it frequently or just occasionally, regulated/unregulated, focused on specific modes aka power/temperature/bypass, one battery/two/three/four? And so on, you get the point.
I know I'm crazy but all that matters at the end, there's no rule of thumb or easy answer to these questions.
Also things one person will love, you might not, but after you answered all these questions for yourself, you can then narrow down to a few mods and do your research, as well as ask questions that might be easier answered. My thought on that, for whatever its worth lol.