To be fair, charging your notebook at 100 all day is going to degrade the battery pretty quick. Using it unplugged until it's low is actually the correct procedure.
It is true that ~70% is a good idea, but most charging controllers are designed to give a full charge because they have no way of knowing when the user wants a 100% battery because they're about to go out or 70% because they're going to be plugged in for a while.
This can be changed in software, setting it to 70-80% or having a toggle is best for the battery.
If you were storing a laptop, it would best be at 50% or so. The battery is under less stress at that state of charge (SoC), so the battery will age more slowly.
If you have OSX, you can use Al Dente[1] to limit SoC to 70 or 80% while using it to reduce battery aging. There may be similar settings on Windows depending on your laptop's manufacturer.
If you can maintain a limited SoC rather than running the battery down, that's most preferable.
Otherwise, discharging lightly (but not below 20% or so) then charging to 80% or so would be a good usage pattern.
It's helpful to know that many chargers are designed to achieve 1C charge rate (this excludes "fast chargers"). That essentially means they go from 0 to 100% SoC in one hour. So start a 30 minute timer when you plug in electronics to charge, and you'll gain about 50% SoC.
Well, no. It seems to be something that spilled over from the smartphone usage patterns. Because for notebooks which are plugged in, the notebook is supplied from the power network and the battery gets charged only if necessary, by applying intelligent logic. For example my Legion notebook only charges the battery when it's below a certain threshold. Think this is by now the case even with the most low-end notebooks. Plus the non-linear nature of consumption on a developer notebook makes the battery as power supply for serious work un-reliable. Try running a few database containers in your local environment while sitting in a one-hour conference pair-programming with video on and tell me how far you get with that 100% charged battery ;)
