@jakejnelsonWhat happens if you level up and put a point in an ability score while wearing an item which sets that score to 19? The answer depends on the specific item you're wearing.
— Jeremy Crawford (@JeremyECrawford) August 30, 2015
@jakejnelson If you increase your Intelligence to 19 or higher while wearing a headband of intellect, the item ceases to affect you.
— Jeremy Crawford (@JeremyECrawford) August 30, 2015
@JeremyECrawford But if I have the headband on, and I put a point in Intelligence, does it go to 20 or stay at 19?
— Jake Nelson (@jakejnelson) August 30, 2015
@JeremyECrawford Assuming it's normally lower than 19.
— Jake Nelson (@jakejnelson) August 30, 2015
@jakejnelson The headband has no effect on the score on your character sheet. The item effectively overwrites a score lower than 19.
— Jeremy Crawford (@JeremyECrawford) August 30, 2015
@jakejnelsonSo the score would become 20?
The ability increase ignores the headband. It is increasing the score on your character sheet.
— Jeremy Crawford (@JeremyECrawford) August 30, 2015