Think about RCs as if they were gasoline for your car.
If you drive fast, you'll probably consume more gasoline, however you may reach your goal faster. If you drive slowly, you can save gasoline, but will probably need to drive a while longer.

You need to trade off the invest (RC) for your possible return (attention, connections, upvotes, etc.).

Practical example: If you leave 10 nonsense comments nobody cares about and pay a high amout of RC for it, it's probably less contributive than leaving 3 really well elaborated statements that may help you to grow your brand.