Lets imagine two designs of some appliance (washing machine).
Design A folows imaginary perfect planned end of life, "potted cellphone" design that has a "ticking clock" and dies exactly after K days and cannot be repaired.
Design B follows "infinite reusability", an imaginary concept where you could replace any component/module you wanted, at time-defined intervals Ki (i=1:N), for the 1/Nth price of a new B appliance (where N is count of components in an appliance). The assumption here is that no serious skills are needed to service it, an indicator shows "K7 time is up, replace component 7" and it is just a matter of popping the lid and putting in a replacement and closing the lid back.
I'd say that in B if N=1 and K1=K then this is equal to A design with "K time is up, replace appliance" message every K days. These designs conceptually differ only in N value.
With modular design B this is a matter of replacing component by component but since none of the components is ethernal, after some time t=T you end up with a completely new appliance.
Some Fun involving piecemeal replacement of component parts.......namely Triggers broom
https://rhodestothepast.com/2018/07/05/daft-as-a-brush-the-ancient-philosophy-of-triggers-broom/
To me a product remains ‘original’, from a functional point of view, if it has the exact same design and characteristics as when it left the factory. Deviation from that original design and functionality, for better or worse, makes it a modified product For a archaeologist or conservator it is a very different story though.
I have a favourite laptop (Dell Inspiron 3500) that was used until its case plastics began to fatigue crack due to flexing in the chassis. I repaired the case cracks with plastic welding and all was well. Some years later I saw a company selling original case plastics for my model of Dell laptop. I bought a complete set of case plastics, installed the laptops chassis into them and the laptop looked brand new Was it the original laptop ? To my mind yes. It’s internal ‘organs’ were original and I had just provided a new set of ‘clothes’. That said, some years previous I had fitted a faster Processor module so it’s ‘brains’ were changed long before the casing. In terms of the right to repair, I was so pleased to be able to buy a new complete casing kit for my laptop at reasonable cost. It was clear that the casing parts were a clear-out by Dell to a parts reseller as the laptop was long obsolete. Did it make sense for Dell to stock complete laptop casings ? They obviously thought so whilst the laptop was current but it became dead money once the laptop went obsolete. Not many people would pay what Dell would charge for a complete casing. I suspect those parts were purely stocked for warranty claim purposes. Back in the latex 1990’s laptops were so expensive to make and buy that the maths may have justified the storage of ‘consumable’ or failure prone parts. I am not sure the story is the same today though. When my iPad battery died, I paid £80 to the nice chap in the Apple store and he gave me a brand new, not ‘refurbished’ iPad. He commented that even though my original iPad was in mint condition, it did not make financial sense to dismantle and refurbish it for reuse. That sort of suggests that an iPad actually costs Apple less than £80 to manufacture.... just my guess though. In the face of low production costs it is only really viable to refurbish or repair equipment that is special in some way, either in intrinsic production cost, data recovery or system compatibility. There are many elderly industrial Electronic systems in use throughout the World.... why ? Well they cost too much to replace, upgrade or to redesign the system they operate within to use modern replacement technology. Win XP is still alive and well in embedded computers within Industrial systems That is where the right to repair can be essential to support the users of such equipment. I was trained to repair almost anything electronic with, or without a schematic diagram. These days a schematic diagram can be essential for efficiency and success. Then there is is the bespoke software and firmware to be considered ! Repairing modern electronics can be a total nightmare if the fault is not something relatively simple to track down.
Fraser
(..) If T has all the N's as factors, so they all wear out at that exact time, then it's indeed time for a new appliance.
It is right away clear that design A can make sense over design B if all the modules have approximately the same expected life.
What happens to the model if we assume different lifetimes of the N sub-components, and also assume different costs to replace them?
[...]What happens to the model if we assume different lifetimes of the N sub-components, and also assume different costs to replace them?Things get complicated but even with this naive model quite a lot can be deduced.
You can see that the cost of replacement matters only when Ki does not equal T.
There is going to be exactly zero demand for a spare component that has Ki=T.
At the other extreme (your N=1 case), the entire appliance is scrapped when the part (however small) with the shortest lifespan fails, including 99% of perfectly serviceable components. Even if heroic efforts are made to recycle the machine, does it really make sense to melt down old (but working) parts to make near-identical new parts for a new machine?
It seems to me that expensive components would end up dominating the model if we account for varying costs.
[...]
One particular case could be solved easily: Prohibition of welding together plastic tanks of washing machines. That is a realy nasty practice, and there is hardly as much resource saved with it as it destroys.
There are some problems with the "A" however.
A perfectly planned component life time can not account for different methods of usage.
(..)Think about how many different ways things can be used.
You need to buy/replace the whole boiler+heater assembly which costs 190 bucks. The same (new) appliance costs...180 bucks. Guess what my friend decided to do ?
2 million Cosori air fryers are currently being recalled over reports of burns, property damage.
You guessed it... they are not being repaired, but replaced. It is cheaper to make new ones, apparently!
>it's probably unsafe in the general case to make it a rule to just let random joes repair them.
What's the problem with allowing Darwinian selection ?
Some Fun involving piecemeal replacement of component parts.......namely Triggers broom
https://rhodestothepast.com/2018/07/05/daft-as-a-brush-the-ancient-philosophy-of-triggers-broom/
To me a product remains ‘original’, from a functional point of view, if it has the exact same design and characteristics as when it left the factory. Deviation from that original design and functionality, for better or worse, makes it a modified product For a archaeologist or conservator it is a very different story though.
I have a favourite laptop (Dell Inspiron 3500) that was used until its case plastics began to fatigue crack due to flexing in the chassis. I repaired the case cracks with plastic welding and all was well. Some years later I saw a company selling original case plastics for my model of Dell laptop. I bought a complete set of case plastics, installed the laptops chassis into them and the laptop looked brand new Was it the original laptop ? To my mind yes. It’s internal ‘organs’ were original and I had just provided a new set of ‘clothes’. That said, some years previous I had fitted a faster Processor module so it’s ‘brains’ were changed long before the casing. In terms of the right to repair, I was so pleased to be able to buy a new complete casing kit for my laptop at reasonable cost. It was clear that the casing parts were a clear-out by Dell to a parts reseller as the laptop was long obsolete. Did it make sense for Dell to stock complete laptop casings ? They obviously thought so whilst the laptop was current but it became dead money once the laptop went obsolete. Not many people would pay what Dell would charge for a complete casing. I suspect those parts were purely stocked for warranty claim purposes. Back in the latex 1990’s laptops were so expensive to make and buy that the maths may have justified the storage of ‘consumable’ or failure prone parts. I am not sure the story is the same today though. When my iPad battery died, I paid £80 to the nice chap in the Apple store and he gave me a brand new, not ‘refurbished’ iPad. He commented that even though my original iPad was in mint condition, it did not make financial sense to dismantle and refurbish it for reuse. That sort of suggests that an iPad actually costs Apple less than £80 to manufacture.... just my guess though. In the face of low production costs it is only really viable to refurbish or repair equipment that is special in some way, either in intrinsic production cost, data recovery or system compatibility. There are many elderly industrial Electronic systems in use throughout the World.... why ? Well they cost too much to replace, upgrade or to redesign the system they operate within to use modern replacement technology. Win XP is still alive and well in embedded computers within Industrial systems That is where the right to repair can be essential to support the users of such equipment. I was trained to repair almost anything electronic with, or without a schematic diagram. These days a schematic diagram can be essential for efficiency and success. Then there is is the bespoke software and firmware to be considered ! Repairing modern electronics can be a total nightmare if the fault is not something relatively simple to track down.
Fraser
You need to buy/replace the whole boiler+heater assembly which costs 190 bucks. The same (new) appliance costs...180 bucks. Guess what my friend decided to do ?That is an example of B-type appliance that has a very high Q so most likely he disassembled it for parts (sold remaining parts as replacement parts). Feel free to protest or make campaigns for access to repair documentation. It does not matter how easily a $190 component is being replaced in $180 appliance. Once you force screws by law, one thing that changes is that the appliance is going to cost $181 because of greater manufacturing complexity. Then you'll get three separate replacement components instead of this one, $190 each. Of course you can hack with some generic parts from lawn mower and air fryer but this is not an idea for the sustainable future, or the goal of right to repair movement, you know.
As you said, this would have changed the selling price only marginally (+ 1$), but, as for the washing machine plastic tanks, the decision to make the appliance more sustainable was not taken. Instead, they opted to run the manufacturing process solely on cost.