You can go below 10% for as long as you want, you just can't go below 0%. Going above 90% is also fine, there isn't any step change in harm to the pack at any g

You can go below 10% for as long as you want, you just can't go below 0%. Going above 90% is also fine, there isn't any step change in harm to the pack at any given percentage, degradation over time just steadily increases the more you charge the pack. Charging to 100% for a few hours before a trip is fine. Leaving the car at 100% for a month would accelerate wear a bit.