Stop loss trade does it make sense

Stop loss trade does it make sense and how much should be the loss a trade can carry and what reward it gives do traders follow this is always a big debate. Traders play a big role in markets and there are big time revenue to brokers and Govt but they losing money has started to worry many big broking house as lower volumes means lower revenue so now many new method are being adopted to make then earn. I see many calls given where the risk is more than the reward which doesn’t make sense for traders and they should immediately reject those kinds of calls are else wait till the stock comes near stop loss to buy. In my view if the reward is 3% and more a risk of 1% would be reasonable but many over the net give calls where risk is higher than the reward and many traders suffer losses due to these kind of calls. There is a thumb rule which one should follow never go short on a stock and bad news and never go long on a stock based on a good news as the bad or good news is already and almost discounted I would quote SBIN where I saw many sell calls based on the outlook of the results and the stock after touching a low of rs.725 spurted to rs.799. Stop loss is meant to protect u r capital erosion as short trades are done to earn more profits with less capital and holding capacity so basic should be always right and one should know if u can arrest u r losses to bare minimum profits would start to flow.