This is optional, but wouldn't hurt you, of course. If you are in good health and physical condition, you can walk the Way without special training preparations. However, it is advisable to take walking excursions to gauge your physical fitness, and also to test and break in your walking shoes/boots. In case you have some sort of physical deficiency, or just simply are not used to walking great distances day by day, it is highly recommended to try your capacity and limits before embarking.
It depends a lot on your needs and preferences. Accommodation prices vary from zero (donativos) to 10 or even 15 euros. If you're not planning to have hot meals every day, you can make it out of 10 euros. Add another 5 to 10 if you plan to have a pilgrim menu or take your share of community dinners.
Some additional expenses may be:
Washing machine: most albergues charge up to 3 or 4 euros
Internet: usually between 2 and 4 euros per hour
An average day's spending would thus be between 15 and 30 euros, assuming that you don't want to stay in hotels and won't usually dine in the town's fanciest restaurant.
The Spanish word donativo means donative, that is, maintained by pilgrims' donations. At such albergues and refugios there is no fixed price for the accommodation, but pilgrims donate as much as they can afford and feel like.
You can wash your clothes practically in any albergue. In most cases you will find a sink for washing clothes, and a rope in the garden where you can hang your clothes. Many albergues have coin-operated washing machines. It is advisable to join others to wash your clothes together and share the expenses.
There is no such thing as a compulsory daily distance — you walk as much you like. On the Camino Francés nearly every town or village has its own pilgrim accommodation, so it is enough to walk only a few kilometers a day if you like.
an average walker's speed is 3-4 km/h
an expert walker's speed is 4-5 km/h
a fast and tough walker's speed is 5-6 km/h
Pilgrims usually walk 20 to 25 kilometres per day, and complete the Camino Francés in 30 to 35 days. Always choose a daily distance that your body can tolerate. Never exploit your resources, because you endanger your entire pilgrimage by that.
Pilgrims usually get up early. In summer they start their way at 5-6 o'clock to take considerable distance comfortably before the summer heat. Usually pilgrims must leave the albergues by 9-10 o'clock at the latest.
Pilgrims walk during the day, and arrive to the their next stop early afternoon. Albergues usually open around 13:00. Pilgrims rest at siesta time, and later in the afternoon they can go sightseeing or just hang around. In the evening they have dinner, meet each other, read, or write their diaries. Sleeping time usually starts at 22.00.
In spring and autumn the schedule mentioned above starts a few hours later.
On your way, you will find bars in almost every settlement, where you can have a tortilla (potato omelet), bocadillo (sandwich) or tosta mista (toasted ham and cheese sandwich in Portugal) even in the morning. You will encounter several places during the day where you can buy food in shops.
If the albergue you stay in has its own kitchen, you can cook for yourself, or you can cook together with other pilgrims. Some restaurants offer three-course menus del peregrino (pilgrim menus), which usually cost between €8 and €12. It is advisable to inform yourself about the settlement where you plan to stay for the night, so in case there are no shops or bars nearby you can buy some food beforehand.
It might also be a good idea to carry some food (e.g. snacks, bread, sweets) with you in case you get hungry while walking.
Ideally, your backpack shouldn't weigh more than 10% of your body weight. Try to keep that in mind when packing. To keep the weight of clothes in your backpack to a minimum, prepare to wash them every two or three days. Also count in the weight of water you'll be carrying with yourself. In case of smaller people, the 10% ratio is unrealistic, so don't be suprised if you can't keep the weight of your backpack under 8 kgs.
If you speak English, German or Italian, communication won't be a problem. If you don't speak major European languages, don't worry. With openness and confidence all language barriers can be overcome. It is advisable to keep a simple vocabulary that includes the most important sentences in the local language. Keep looking around, because there is always a chance that you find a fellow countryman near you. And don't worry, you will meet many kind and helpful people on the Way.
If you are still uncomfortable, organize your Camino to walk with a companion.