The scrap recovery arm costs 50 scrap and Gives you +10% scrap on acquisition other than selling items (rounded down.) Given that you have to spend scrap to earn scrap, at what sector does it make sense to invest in the SRA? I'd imagine you'd want to have a significant gain to make up for early scrap disadvantage.
This question's answer will vary based on difficulty, as that impacts scrap rewards as well as the necessity for early scrap.
Best Answer
In the first couple sectors, I think you easily make about 100 scrap per sector. As you move up, that amount increases to 200 or 300 per sector (assuming you are defeating all ships rather than fleeing or avoiding them). So I'd say that as long as you get it before the end of sector 4, it definitely pays for itself. After that, it gets to be risky, but could still pay for itself even if you pick it up in sector 5 or early sector 6.
There is also the opportunity cost of taking an equipment slot and not having the 50 scrap to spend on something else. I'd probably rate it as awesome in sector 1-3, good in 4, and iffy beyond that.
Comments talk about the Asteroid Field event, but I think that is rare enough that I wouldn't really take it into account. I've bought the arm numerous times, and gotten to take advantage of that event in maybe 10% of them.