Can one hostel across Europe without reservations?

A reader named Brian recently weighed in with the following question:

This September I will be making my way from the U.S. to London to Munich for Oktoberfest. After that I want to venture around Europe for several weeks. My main concern is where to go and which hostels to sleep in. I’d rather not make reservations everyplace, but I want to make sure I’ll have cheap places to stay as I travel.

This is what I told him:

My first advice would be to get a good guidebook(s), which will give you plenty of advice on where to go, where to stay, etc. Though you’ll want to be independent of guidebook info from time to time, a good guidebook can make a big difference in your trip!

A couple other things will be helpful as you journey across Europe. One is word-of-mouth, as other travelers you meet in these hostels will have good ideas for other destinations, hostels, bargains, etc. The other option is the Internet, as message boards at places like Bootsnall.com or LonelyPlanet.com will give you plenty of ideas for travel (you can post your own questions there as well). As for hostels, online bookers like Hostels.com can help you plan in advance — though September is not high season, so you should be able to easily find hostel beds as you go. The big exception to this is Oktoberfest in Munich, which is always jam-packed — so be sure to plan your lodging as far in advance as possible. You might also want to make advance plans for London, since that is your first destination, and advance planning may help you save money in that notoriously expensive city.

Of course, you should also look into hospitality exchanges, like Servas, Couchsurfing, or Hospitality Club, which allow you to stay for free with engaged local hosts across Europe.