staying in hostels, Fiji or maybe Cook Islands

I'm a newbie here... been reading the posts and haven't seen this answered: Do we need to make reservations ahead of time for the hostels in Fiji? We want to take a trip there in August, stay in hostels, swim, snorkel, "experience Fiji". I would like to be able to leave our itinerary somewhat open, not have to be at a certain place at a certain time... move on to another location when we want. On the other hand, I don't want to get there and find out all the good places are booked for our entire stay. Would we be able to find accomodations 'on the fly?' I also haven't defined our exact dates of travel... if we do need reservations, how soon would we need to do that?
Do you know if the same would apply to Rarotonga? (that's also a possibility)
Also, what are the reef shoes that many refer to?
Thanks

Hostels usually have accomodation available without booking in advance.
Reef shoes are rubber soled shoes that slip on and protect your feet from coral cuts and stone fish etc.

For the Cooks, you might want to book the first night in advance. Check out www.ck for places, and lots of reviews on here.

You WILL have to name the place you are staying for the first night when you get to Immigration. Well, you need to name SOMEPLACE, like Vara's, etc., even if you won;t be staying there! So, you might as well pick a place and book the first night. Lots of flights arrive in the middle of the night, so having the first night booked is handy.

Reef shoes are also called "water shoes" in some places. You can get them for US$10-15 in most major sporting goods stores in the US, or in large dept stores like Target etc. in the spring and summer. Even Long's Drugs, etc etc.

Due to lack of flights between Fiji and the Cooks now, you would probably have to do Fiji OR the Cooks, unless you do one on the way down to NZ and the other on the way back, on Air NZ.

I'm not sure what you mean by 'hostel' on Fiji. There aren't many (any?) of the official IYHA sort. There are the so-called backpacker resorts with dorm accommodation available -- maybe that's what you mean anyway. For August I'd expect there to be no problem finding accom, especially if you're flexible about where you stay. It's always a trade-off.

However, if you ever have a particular place in mind, I suggest that you at least phone ahead a few days in advance, when you have fixed your itinerary. Some places are small with not much accom, and on any given day they might be full.

I travelled around for a couple of months, and always managed with no more than a phone call to my next stop a day ahead of time.