depending on circumstances; at one's convenience
Used to indicate that something will happen or be decided based on the situation or one's availability. Often appears in phrases like 都合次第で or 都合次第だ.
Whether I can attend depends on my schedule that day.
I'll decide whether to go on the trip depending on work circumstances.
次第 is a suffix meaning 'depending on' or 'as soon as'. 都合次第 specifically combines it with 都合 (circumstances/convenience).
都合 means 'circumstances', 'convenience', or 'arrangement'. 都合次第 adds the nuance of 'depending on' those circumstances.
Compound of 都合 (circumstances, convenience) and 次第 (depending on). The combination is transparent and follows the productive pattern of noun + 次第.