As I've already hinted, I hate having to erase and recalculate repeatedly. It wears out character sheets, for example. Damage is a big offender here. My solution isn't exactly original; I'm sure others have done it, and I was inspired to do it when I read how Sorcerer tracks damage.
Write your total hit points on your character sheet as normal. Do not change this except when your character's level changes (or any other time your character's maximum hit points changes.)
Get a sheet of scratch paper at the beginning of the expedition. Label it "damage". When you take damage, mark tally marks on this sheet. Use the common practice of marking four tallies, then crossing these diagonally to make the fifth tally mark (it makes it easier to count.) Put two groups of five on each line. When total damage is greater than or equal to hit points, your character is dead (or unconscious, or whatever your specific system says.)
If you follow the "ten damage to a line" convention, you can pre-mark the scratch sheet to avoid counting tally-marks during play. Drop the last digit of your hit points; count down that many lines on the scratch sheet, then draw a horizontal line. When tally marks reach that line, the next few points of damage are your last.
Only erase tally marks when the character is healed. To completely avoid erasing, divide the sheet in two vertically and label the other side "Healing". Mark healed hit points the same way as damage. You can now eyeball your character's state of health. When the two sides are equal, your character is at full health. When there's more tally marks on the damage side, your character is wounded. Unfortunately, this means you can't pre-mark your near-death state as just described, but it's still pretty simple.