Using 'heedless' implies negative judgment towards someone's actions or attitude. His heedless spending got him into debt.
Pro Tip 2/3
Possible Outcomes
'Heedless' often suggests that bad results could follow because important things were ignored. The hikers were heedless of the weather forecast and got caught in a storm.
Pro Tip 3/3
Inattentiveness
'Heedless' describes a lack of attention but doesn't always mean it was intentional. The child was heedless of her surroundings and lost her way.