Something that costs money or effort now but is expected to bring enough benefit to justify that cost.
“Paying extra for the ergonomic chair is a worthwhile investment for your back health.”
“I think the certification course is a worthwhile investment if you want that promotion.”
This phrase is useful in Task 5 when persuading someone to spend more upfront, such as choosing the pricier laptop or gym membership. Use it to reassure the listener that the extra cost is justified, then quickly explain the payoff (durability, health, career benefit) to make the persuasion concrete rather than abstract.
Synonyms: money well spent, a smart investment, worth the cost