There will be many posts offering thoughts, opinions and anecdotes about this issue. Everyone has their personal thoughts and preferences on this issue. However, my counsel is to first assess what your personal style and tolerance level is.
Do you prefer private lodging, with a locked door and en suite bathroom? Do you prefer to share one bed with your wife? OR, are you experienced with, or willing to sleep in a bunk bed, in a large room with a dozen or more new friends, who you may have met on the days' walk? These people, men and women, will be from all over the world.
The former, private accommodation, is found in hostals, casa rurales, and some private albergues. The latter, group dormitory, is found in the traditional and ubiquitous albergue.
Each pilgrim has their own story and background. But, general attributes to sleeping in an albergue include: sharing bathrooms and shower with all the others, having people sleeping very close to you who snore, toss and turn, get up repeatedly to use the toilet, and perhaps do not adhere to the same standard of bodily hygiene as you.
Also, and most famously, in every albergue, there are those who rise before the sun, at 05:00 - 05:30, during your final hour of sleep, to get a head start on their day. Unfortunately, few persons are mindful of their fellows. They tend to make just enough noise to wake you up as they gather their belongings in the dark, use flashlights, pack their rucksacks and speak to their friends. Yes, it is rude and selfish, but it is part of daily life in albergues on Camino. You are not expected to like it, but you are expected to cope.
Personally I learned from experience over five caminos that I perform better if I stay in private rooms. I admit that I do snore, do use the toilet frequently, and do toss and turn. But, I am also highly susceptible to bronchial infections. it only takes one person with a cold or bronchitis in any dormitory style sleeping place to infect everyone.
So, I do everyone a favor and plan and budget ahead to be able to afford private lodgings whenever available. I will stay in an albergue, preferably a private albergue, but only as a last resort, if it comes to that or the church steps.
I also book about three days ahead as I walk, starting with a hotel at St. Jean for two nights while I make final preparations and get over jet lag. If coming from North America, one generally does not arrive at St. Jean until around 6:00 pm. So I give myself that first night to decompress from the journey and the full, following day to obtain last minute supplies in town.
So, I pre-reserve the St. Jean Pied de Port hotel for the first two nights I am over there, my first night on camino, usually at Refuge Orisson, and at Roncesvalles. However, the big albergue there in the former seminary, is run by the Dutch Friends of St. James and is a very good place to stay, so I do. Once I get to St. Jean, I go online and start reserving space beginning with the day after Roncesvalles. This is the plan that works for me.
IMHO, the two best places to find and book lodging in advance, particularly on the
Camino Frances is
www.booking,.com and
www.gronze.com (Spanish only). It also helps if you learn how to write a polite reservation request in Spanish, using either the Google of Microsoft translation apps on a smart phone. You can send this ahead in an e-mail message to make a reservation if the property does not have online booking.
I hope this helps.