I am a first time backpacker about to start backpacking through Australia. But before I leave I have a few questions.
For example: When I stay at a hostel for 2 nights or more. Is it safe to leave my backpack in the hostel, when I am walking around in the city/village where I am staying?
Do they have lockers? And is their a lot of theft in hostels?
Also, I have to bring medicines and they need to be cooled, do most hostels have fridges or anything where I can keep them cool and freeze in the Icepacks (to cool medicines when travelling) that I brought?
Leaving a backpack with dirty clothes is perfectly fine - no one is going to steal that. Just don't leave your valuables (mp3 player, digital camera, wallet, etc). Most hostels do have lockers in the dorm rooms, which are useful to put your stuff if while you go take a shower or somesuch, but do note that these aren't secure enough to rely on to keep your valuables safe for extended periods of time - if you need that, put them in the safe at reception. There's not a lot of theft, but it's also not completely unheard of, especially when you're careless with such tempting items.
I don't think I've encountered any hostel in Australia which didn't have fridges - much better than Europe in that regard. Not many freezers around though, so you might have trouble with those ice packs.
I used to just leave my backpack in the dorm and not worry about a locker. However there are usually lockers under the bunks which can be secured with a padlock - therefore it is always handy to take your own padlock with you as this saves having to place deposits on them in hostels.
With regards to your medicines there are fridges avaliable in hostels to store them in - although I don't recall coming across that many freezers!
Hope you have a fantastic trip
Most good hostels will have lockers, check this out on the website before booking. Make sure you have your own padlock. I've just been the victim of theft in a hostel in Adelaide - shoes and some money (shoes for gods sake!!) - that didn't provide lockers so it is important to have them. Fridges won't be a problem unless for you go Outback