According to multiple sources, including Battery University and Samsung, the best practice for preserving phone battery health is to keep your battery topped up somewhere between 20% and 80% most of the time. Here are some tips to keep in mind:

• Charge regularly: Most smartphones have a lithium-ion battery that lives longer when charged regularly. Unlike the nickel batteries used in older phones, lithium-ion batteries do best when kept above a 50 percent charge. Repeatedly allowing the battery to drain fully may shorten its life and decrease its overall capacity.

• Avoid charging to 100%: For optimized battery life, your phone should never go above 80 percent or below 20 percent. A lithium-ion battery doesn’t like to be fully charged, and it doesn’t like to be fully charged and warm. Charging from 0% will cause a lot of heat, and from 80% up, fast charging becomes less efficient.

• Avoid cheap chargers: Cheap chargers can damage your phones battery. Its best to use the charger that came with your phone or a reputable third-party charger.

• Avoid charging overnight: If you charge overnight, you are guaranteed to miss when the phone exceeds the magic 80% mark that is best for extended long-term life. While most modern smartphones have built-in sensors to shut off charging when they hit 100%, if still turned on they will lose a small amount of battery while idle.

• Use fast charging in moderation: If you want to hold onto your phone for several years, you should use fast charging in moderation. The convenience of getting your phone to 100% in half an hour does come with a trade-off. As the battery charges faster, it also heats up faster, which can degrade the battery over time.

In summary, its best to keep your phone battery between 20% and 80% most of the time, charge regularly, avoid charging to 100%, avoid cheap chargers, avoid charging overnight, and use fast charging in moderation.