My point is the cost. Let's say you buy your shiny new iPhone for $1000. 5 years later the battery needs replacing. Maybe your phone model is still available (u

My point is the cost. Let's say you buy your shiny new iPhone for $1000. 5 years later the battery needs replacing. Maybe your phone model is still available (unlikely, but let's just imagine it)... normally Apple have $200 or $300 gap between the current and last year's model, and $100 between the previous generations. Let's say a brand new phone exactly the same as your 5 year old phone is now $500, so your old phone with its worn patches and scuffs and maybe the odd dent or scratch here and there is worth less. Now much less, who knows? Maybe it's been kept in pristine condition. And you take it to a shop for the battery replacement, they say it'll be $100 for a new battery. Is it worth it? Maybe. $100 for a phone that's worth at most $500. Maybe your charging port is getting a bit wobbly. Maybe your headphone jack is full of lint (OK, cruel joke), whatever. Either way, the cost of paying the shop to fit a new battery is a big chunk of the phone. I've had several new batteries for phones in the past - for my old HTC One, which I think was about £5-8 (maybe $10) and i just popped off the cover and slid out the old one and slid the new one in. Getting the new battery at that price was a no brainer, even though I'd actually already got a NEW phone by then and was planning on just keeping the old phone as an emergency spare. If I had to pay £100 to keep it going, I wouldn't have bothered. I've also had the old Nokia ones where the back that popped off actually was the battery. Those phones weren't water proof, but it'd be possible to have the same style battery connector with the phone side fully waterproofed, those 4 contacts on the back and the battery clipping to it. It'd probably be slightly thicker than current phones, but as most people put their phones in a case anyway, maybe well see a new class of integrated battery and case products that provide protection whilst not being much thicker than a stock battery.