Dear Sue, please don't fret, it's not necessary for you to. I wish I could give you the peace and knowing that all is well and you need not worry. This year I am going back to walk the Camino Francés for a sixth time. I adore the trail, the history, the beauty, the wonder of it, everything about it. I've walked in every month from June to October, including the 2010 Holy Year and two arrivals in Santiago in time for the July 24th celebration (thousands and thousands of people there for that), and only once did I arrive at an albergue that was full and resulted in my walking on to the next town. It was Ferreiros, after Sarria, where the albergue only has about 22 beds, and my friend and I arrived at 7:30pm. Of course it was full.
We could have stayed at a farmhouse down the road where beds were offered to us but we chose instead to walk on to Portomarin and that was a delicious adventure unto itself.
People have different experiences on the Camino so I won't guarantee you'll never find full albergues. They do fill up. But most of the "bed race" game is a state of mind, and attitude and intention have much to do with not getting caught up in it, as does common sense. If you finish walking by 2pm or so, chances are good you'll have no problem. If you stay in places in between the stage beginnings and endings in guide books, that also can help. But really, you will quickly find out how things flow on the Camino. I often think it's quite magical the way pilgrims find places to tuck into for the night, as many as there can appear to be walking throughout the day. (And some like to walk into late afternoon and evening.)
I've also stayed at several albergues where floor mattresses were set up and space made for extra pilgrims. I hope that eases your mind somewhat, because a joyful journey awaits you.
Buen Camino! I hope you get to see oceans of beautiful red poppies as you walk.
Rachel