Travel insurance is like car insurance. You pay for it hoping that you'll never need to use it, but if you do need it, you're glad that you got it.
Upon ordering it, you will get an email confirmation with contact info and scope of the coverage.
I, personally, have purchased the travel insurance (from this website
) 5 separate times, 15 months total (3 months at a time), over the past 2 years. Specifically, when my girlfriend comes to LA form Madrid, she stays here for 3 months each time. To be safe, I purchase this for her just in case there is an accident or problem.
Thankfully, we have never had to use it! I definitely recommend it, though, because you really do never know when you might need it. Oh, and the one from Travelpunk.com is a good place to get it.
You can also add it on an individual day to day basis when you book hostels from the hostel search engine.