Refers to something that is done or happens on a regular, habitual basis; often used adverbially as 常日頃から or 常日頃の.
I always take care of my health on a daily basis.
His everyday efforts paid off.
Standard kanji spelling.
Mixed kanji-kana spelling; less common but still encountered.
Compound of 常 (つね, 'always') and 日頃 (ひごろ, 'usually, everyday'). The exact historical derivation is uncertain, but the combination reinforces the meaning of habitual or constant action.