A RSI of 70 - 80 is usually followed by a decline in SP, so if you are in the money by then, lighten and make what you keep a "free ride".
A very low RSI can indicate that the SP is a falling knife, time for many to activate stop losses or dump.
However, the RSI should not be the only indicator for the above. All indicators have to be taken into consideration. Add your own experience in share trading and you should be OK, yet some losses will always occur.
