So lithium batteries are a pretty funky power source. I'll try to do an ELI5 on lithium battery degradation. There is some natural corrosion that occurs on the cathode and anode, the flow of electrons just messes them up, so expect to lose 10-20% of the batteries capacity over time. The total amount of charges don't really bother the battery, it's all about amount of charge used. So if you drain a cell to dead (which coincidentally is really hard to do, and if you ever actually drained a lithium battery completely for a prolonged amount of time, it will forget how to hold a charge and just stop working). So a continuous discharge of 75% or 3 sets of 25% will degrade the battery a similar amount. Almost all lithium chargers worth their salt have trickle charge technologies to prevent over charging. They will stop charging at 100%, and typically resume charging at 95%. This is why sometimes you will disconnect a phone from a charger and a few seconds later it drops a few percent. The worst thing you can do to a lithium battery is heat it up. The higher the temperature, the faster they degrade. In addition, the higher the amount of charge in a battery, the more damage will be done by heat. Some would argue that the discharge and recharge speed could cause degredation, but we don't really have to worry about that with dash charge phones. We don't discharge phones fast enough to generate alot of battery heat, and the heat from the recharging process is mostly in the charger itself. In conclusion, charge your phone for however long you want, just make sure to not leave it dead for too long, and to keep it cool by not covering it up or placing it near a heat source. Luckily for us dash charge users, the majority if the heat generated by charges is off loaded to the charger, not the device itself. If you really want to make sure the battery lasts long, keep extensive gaming to a minimum, in order to keep the phone cool.