Rip question

I was just reading up on rip currents and now know how they are created and can be spotted. I was wondering though, is there any way of knowing when they are useful to take you out back and when they are just plain dangerous.
I read they can span from a width of 20-100 metres and can travel up to a kilometer out to sea, is there any way of knowing from the beach where it stops?
They seem useful on heavy beach breaks but in an unknown environment is it dangerous to use a rip current if you do not know the strength of what you are getting into?
Any help would be great
I read they can span from a width of 20-100 metres and can travel up to a kilometer out to sea, is there any way of knowing from the beach where it stops?
They seem useful on heavy beach breaks but in an unknown environment is it dangerous to use a rip current if you do not know the strength of what you are getting into?
Any help would be great
