Leveling up will be based on achieving a worthy challenge or goal. preferably once every month or two.
Resting & Healing:
A long rest is a minimum of 8 hours rest with no more than 2 hours of light activity. During a Long Rest a character will heal a number of hit points equal to half their Constitution Score. If you do not complete a long rest within 48 hours of ending your last one, you must make a DC 15 Constitution Save (+2 for each 24 hours after this) or gain a level of Exhaustion.
A short rest must be at least 1 hour of light activity. You do not gain hit points during a short rest but do regain spell slots or other short rest benefits.
When a character reaches 0 hit points they become unconscious and are considered to be dying. A Dying character must make a successful Constitution save, DC 20 – CON, in order to become stable again. a DC medicine check from another character can give you advantage to the death save.
If your hit points reach the negative of your Constitution then you have Died. All healing raises your hit points from your current and does not default from 0.
When it is determined that no small amount of luck would be needed and no other skills seem applicable a PC may make a DC 15 Luck check (guidline) to see whether things are in their favour.