Resilience - Resist Sleep

Sleeping is essential for a person's well-being and proper bodily function. It is still unknown how long exactly a being can survive without sleeping, yet effects of sleep deprivation are quick to show when a person goes without sleep for even a single day. While dying from sleep deprivation is uncommon, there have been enough documented cases of it to raise it as a serious concern. 
A character must make a Resilience check once per every 24 hours they spend without sleep in order to combat the effects of sleep deprivation. Each time, the check becomes more difficult as your character can only resist the effects for so long.
The effects of sleep deprivation are shown in the following table. Each time your character fails their Resilience check, they go further down the table, suffering all the effects from of the current sleep deprivation stage as well as the others from previous fatigue stages.
As a side note, remember than without sleeping, recovering strain is more difficult. A good night's rest also allows a character to heal 1 wound.
In most adventures, characters will have their full night of sleep even thinking about it. They rest at an inn, a tent, a hammok on a ship, or even against the trunk of tree. Yet, some situations may occur in which the character cannot find a safe spot to sleep or they cannot spare the time to sleep. The following table only presents negative effects for going three nights without resting. If it is already rare that characters have to make these checks, going without sleep for that long is improbable at best.
The difficulty starts at Average (dd) when the character spends their first 24 hours without sleep. After that, regardless of the results of the check, the difficulty increases by 1 for every 24 hours beyond that first check.
EXAMPLE OF A STAY AWAKE CHECK
Kyp is a crew member of a merchant ship. After his hard day of work climbing up the rigging, moving sails and mopping the deck, he is quite tired and enjoys his share of rum before going to his bunk. Not even an hour later, the captain rings the bell and calls all crew on deck. A violent storm has come out of nowhere and the crew was caught off guard. Kyp is now working a double shift to keep the ship afloat. The hours go on and the storm only dies at dawn. Totally exhausted, Kyp yearns to get back to sleep but the quartermaster rings the bell again, announcing the start of the day and thus, their work shift.
Kormak has been up for 24 or so hours and is starting to feel very tired. The GM calls for a Resilience check to stay awake.
The check starts at Average (dd). The GM adds b b to the check. One for the exhausting day he had before and another one for the really hard work over the night. Finally, the GM adds a b for the short rest he was able to enjoy right before the storm.
The check generates ffaa. Since he failed his check, Kyp is now suffering from sleep deprivation. He won't heal as much strain after encounters and will add b to all checks. Kyp's player spends the first a to have their character remove the b on his next skill check. Working in the rigging, Kyp will need to make Athletics checks and the player wants to mitigate that penalty on checks. The other a is spent to recover one strain as Kyp takes a moment to admire the beautiful view and reminds himself that the pay at the end will be worth the trouble.
Should a situation that would prevent him from sleeping again arise once more, he would have to make a Hard (ddd) Resilience check, adding b to his check as per the stage 1 penalty.