Should we book our hostel rooms now, or can we do it as we go?

You shouldn't have a problem if you wait but if it makes you feel more comfortable book them ahead of time.

I would book'em now. That way I don't have to worry about it when I cross the pond and plus I don't want to be using up my valuable vacation time scouring for a place to stay.

The vast majority of hostels aren't booked up until they fill up in the morning, if at all. I think calling ahead either in the morning for a spot or a day ahead gives you the best chance of finding vacancy while still allowing flexibility in your travel schedule.

Some hostels have a reputation for filling up fast. In those cases, you almost have to plan on reservations or just find another hostel in the area.

Look at hostel reviews, you will get an idea which ones need reservations.

If this is your first trip, I would book in advance the first two or three days and at least the last night or maybe two. When we travel we always book the first and last night and wing it in between. Once you are over jet lag, met some people, exchanged some stories, and begin to develop a little confidence with what you are doing, you will be OK. And, besides, train station are not that bad for over night. The floor is a little hard and it can be noise with all of the other people sleeping there. There are worse places.

Definitely start looking and bookiing now after careful research.

Here are a couple of sites that I used along with asking question on here and on the Thorn Tree.

http://www.bug.co.uk/reviews/hostels/Europe/index.htm

http://www.hostelz.com/hostels-in/Western-Europe

Once you have made your reservation do confirm a couple of days in advance. Print the web page with their address, directions to hostel and phone number.

As you can see, no real concensus on this question. First, you will always find a place to stay, and with a short list of options, you can usually find a place to sleep quicker than most of the "pre=bookers" can locate their hotel. Do not pre-book every night, give yourself some flexibility. Do create a list for each location of several options, maybe as many as 5 or 6. The idea of pre-booking your first night(s) and maybe your last is good, hey you know where you will be!Consider the destination; Paris, maybe a good idea to book ahead, more out of the way places, just as well to wait or call ahead a day or two. On a given trip I might have a few major destinations booked but leave lots of open nights in between.

I would book in Paris, if you are goign there for sure, for such a large city, they don't have much in the way of hostels, and of those that are in Paris a lot of them were not very nice. Paris is my second least favortite city for hostels (Milan being the first), so try and book early to make sure you get a good one. Check out reviews on hostelworld.com

I agree with what Frank suggests. It's nice to have a reservation for the day you arrive. It's one less thing to think about on a hectic travel day.

The other hard date you have is flying home, having a reservation for the night before leaving ensures you will be located conveniently for getting to the airport.

I only book in adavance hostels/hotels in the country I go to first, because I never know how long I am going to stay. There are less people travellinf in September, so it shouldn't be a problem .
Enjoy Europe!

I personally like to have it booked before I go so that I know I have a hostel bed in a clean & safe neighborhood -and so I don't have to hunt one down when I arrive to the city. However, I can see how some would like to plan as they get there (my brother is one of those people and he's never had any major problems). I agree for Paris I would book in advance. I have stayed at AIJ in Paris both times I have been there. The first time I found it because everything else was booked, so I was looking for hostels that weren't on hostels.com or hostelbookers.com and found the AIJ hostel. Luckily they got me in. I stayed there the 2nd time after reading crappy reviews on every other hostel in downtown Paris. Here is AIJ's website: http://www.aijparis.com/ You cannot book online, you have to send them a fax. Minor complication, but definately worth it. It is very clean, they actually have a lock-out everyday to clean. But it is very basic too, very Rick Steve's-esque. It is also a short walking distance from the Bastille, so very central.