Like making anything last, don't operate at the limits of its envelope.

   * Limit max temperatures
   * Reduce maximum currents in and out
   * For lithium batteries, limit peak charge to 3.92V, do *not* charge to over 4.1V or 30degC

I can't find the specific research study, but NASA did a study that last I read was going on for over 30 years with a neglible drop in capacity by only operating in the flat portion of the charge/discharge curve. The result is that properly speccd battery packs (probably > 1.5x most battery packs) can last indefinitely. For my cordless tools, I get the largest modules I can (5Ah). I have a single slim 2Ah module for fitting in tight spots.

*edit, when using a cheap intermittent high current device, like a hand vacuum, apply a duty cycle, like 30 seconds on, 10-30 seconds off to prevent the internal battery pack from getting too hot. These kinds of consumer goods have the smallest battery pack that will outlast the warranty.

I really wish battery charge profiles were codified in QR codes on the modules themselves (besides existing on an I2C bus).

Short-Course on Lithium Ion Batteries https://ntrs.nasa.gov/api/citations/20190030819/downloads/20...

battery aging dataset (appears dead) https://c3.ndc.nasa.gov/dashlink/resources/133/

https://www.nasa.gov/wp-content/uploads/2021/10/3-nasa_batte...

https://ntrs.nasa.gov/api/citations/19990032333/downloads/19...