Ask HN: When should I apply for a patent(and if I should)?

Hi,

I would like to ask you when it's better to file for a patent. I have an idea for a system(software+hardware) and I could turn this into a prototype in roughly 6 months.

The question is, should I apply for a patent now, with only the design on papers or should I wait till I have a working prototype?

And a bigger question, is there any point in applying for a patent in general? I mean, if you manage to get your product out in the world, before everyone else, do you really need protection?

Thanks