What I ask of manufacturers is that at least the battery isn't glued or soldered in, and that there are clear instructions on how to unscrew the back of my phone to replace the battery after it starts dying out. That, and make it easy to take off the back (no adhesives (looks at you apple), and no taking out the front screen to access the battery), and make it easy to buy a genuine battery from the manufacturer's website.
I think that's a good compromise of thinness, ease of manufacture and ease of replacability.
That is a sad comment.
Yesterday's battery technology ensured sufficient energy density to make _all-week_ long battery life a reality. Yes, those were much weaker phones computationally, but I'm fine with staying with just phone calls, SMS and calendar when I'm low on battery, for an extra week...
However there are certain features that a smartphone gives which I wouldn't give up. Navigation with google maps, being able to do banking services on the go with my bank's app, being able to review flashcards with the Anki app, having my railcard/tesco clubcard/nectar card on my phone and never losing it, being able to check any important emails, checking the news if something breaking happens and I need to know instantly.
Heck, we praise Apple for bringing services like calling an ambulance for you if your pulse shows a certain pattern matching a heart attack (via the apple watch), and we also praise smartphones for actions like alerting people for emergencies like a terrorist attack or issuing weather warnings. I wouldn't give up any of those features just to have a dumb nokia phone with a week-long battery life.
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Also - Smartwatches are silly IMHO; and people can be alerted just fine with a voice or text message.
The previous phone I had, since I had been burned repeatedly by phones I was otherwise happy with but the internal battery didn't last a year, I decided to shop around for the few remaining Android phones with decent performance that had an easily replaceable battery. I had to pick a model from late 2016.