A few pounds a trade feels like nothing — but it's charged on every trade, it never has a losing day, and what matters is its size next to what each trade makes. A big edge shrugs it off; a thin one gets eaten alive. For active traders, costs are often the biggest position they hold.
Takeaway: It's not the size of the cost — it's the cost versus your profit per trade.
→ Feel it in: The cost of trading