Do countdown timers work in my industry?

As an e-commerce business owner, I'm skeptical about whether countdown timers will actually drive conversions in my specific industry. I've seen them used in some sectors but I'm unsure if they'll come across as genuine urgency or feel like a cheap sales tactic. I want to understand if countdown timers are universally effective or if their impact varies significantly across different product categories and customer segments. What scientific evidence and industry benchmarks exist to validate their effectiveness?