I'm backpacking in June/July in Czech Republic, Hungary, Slovakia, Croatia, and Slovenia. Will I need to book youth hostels in advance or can I just turn up and get decent cheap ones on the same day??
Probably best to phone ahead, although i've never been to slovakia places like dubrovnik and prague are packed with backpackers, the good news is in prague and budapest you can upgrade to hotels fairly inexpensively if it's necessary.
Great choice of location anyway, have fun!