The First Day
1. One should not say Tefilas Haderech while still in the city before starting out on the journey .
2. Tefilas Haderech should ideally be said within the first parsah after leaving the city and preferably after traveling one mil outside the city .
However, one may also say the Tefilas Haderech after being 70 2/3 amos outside the city .
3. As long as there is a dwelling located within 70 2/3 amos of the previous dwelling, it is still considered within the city limits, even if this situation extends for many miles and during that time one should still not say Tefilas Haderech.
4. There is a minority opinion which allows, and in fact requires, the saying of Tefilas Haderech before departing the city once all arrangements for the trip are completed and he will definitely be traveling
5. If one does follow the opinion of the Taz with all its stipulations , saying Tefilas Haderech before the start of the trip, he bedi’eved fulfills his obligation .
6. There are a number of Chassidic groups that do in fact, say Tefilas Haderech before leaving the city. They insert the Tefilas Haderech at the end of the berachah of “shomei’ah tefilah” in the Shemoneh Esrei closest to their departure .
7. If one is traveling by airplane and the airport is located outside the city — even if there is a distance less than a parsah between the city limit and the airport — one should say Tefilas Haderech in the car, taxi or bus that is taking him to the airport. This should be said once he is outside the city limits, and not after takeoff.
8. If the airport is located within the city limits, then one should wait to say Tefilas Haderech until after takeoff.
9. When traveling by ship, one should also wait until the ship is beyond the city. However, if he says Tefilas Haderech before departure, either before boarding or while on the ship, he has fulfilled his obligation .
10. Under normal circumstances Tefilas Haderech is said just once a day , even if one is going round trip in the same day, or making a temporary stop for resting or sightseeing and then continuing on his journey.
11. If one did not say Tefilas Haderech during the first parsah, he may recite it with a berachah throughout the rest of the journey, unless he has reached the final parsah outside the city limits of his destination. However, if he is already close to the final parsah before the incoming city and he realizes that he did not say Tefilas Haderech, he should say it without the closing berachah.
The Second and continuing days
12. On the continuing days of a trip, when there will be actual traveling [and one has lodged the previous night], one must say Tefilas Haderech with the concluding berachah
13. When one is journeying on a ship, which is a continuous trip not involving any stopover on land for the night, the status of Tefilas Haderech is questionable. Therefore, it is advisable to say the Tefilas Haderech each day of the trip, omitting the concluding berachah.
If he wishes, on each day of the trip he can insert the Tefilas Haderech as part of the berachah of “Shema koleinu” in Shemoneh Esrei [and thus not omit the concluding berachah, since “Shema koleinu” concludes in the same way.]
The same would apply to any mode of travel — train, bus, car — that involves continues travel without overnight lodging in an inhabited area.
14. On the proceeding days, one does not need to wait until the actual trip to say Tefilas Haderech. He may say it as part of the morning berachos, preferably after “Hagomeil chasadim tovim,” or during the berachah of “Shema koleinu” in the Shemoneh Esrei prior to his departure.
15. When one is on a continuous journey, he should not say Tefilas Haderech the next day until after sunrise. If he sleeps during the night stretch of the trip and wakes up after dawn and will be saying the morning berachos [but he will daven later in the day with a minyan when he arrives in the city], he should say Tefilas Haderech immediately after the berachos. Otherwise [if he will daven later, on the train, etc.] he should say it in the Shemoneh Esrei of Shacharis.
16. If he lodges during the night and wakes up before dawn to continue his trip, he should say Tefilas Haderech while it is still dark. Generally, the Tefilas Haderech one says during the day is good until it gets light the next morning, but since he has slept, it is considered a “diversion of one’s thought” ( hesech hada’as) and he needs to say it again, even before it gets light.
17. It appears from many poskim that Tefilas Haderech does not need to be said during non-traveling days, i.e. when one is staying in one place for vacation, business, etc.
18. Rabbi Yosef Y. Schneersohn related that his father Rabbi Sholom DovBer, when traveling, even when spending months in one place, would recite Tefilas Haderech every day after davening, omitting G‑d’s name at the conclusion.
19. From discussions that the author has had with various rabbanim of Lubavitch it would seem that the above mentioned directive of Rabbi Y. Y. Schneersohn does not apply to those who live in two different places, such as people with summer homes or yeshivah and seminary students living in dormitories, overnight camps, and the like.
Changing one’s travel plans during the trip
20. If one has in mind to stay overnight at a certain location when reciting Tefilas Haderech and after arriving and stopping at that location he changes his mind and continues further or returns home, he must repeat Tefilas Haderech.
21. Even if when saying Tefilas Haderech one does not have in mind any specific lodging place, but during the trip he decides to stay over at a certain place and then after arriving and stopping changes his plans, he must also say Tefilas Haderech a second time that same day.
22. The reason for saying Tefilas Haderech a second time is that it is similar to saying a berachah over food with the intention of eating a specific food. If one then changes his mind and wants to eat other foods, he must say a second berachah, even if the food requires the same berachah as the first food, since he had no initial intention of eating the other food. Similarly, Tefilas Haderech must be repeated that same day since there was a “diversion of thought.”
23. When one is traveling with a group and he is not aware where the group is stopping, he does not have to repeat the Tefilas Haderech if there is a change of plans along the way.
24. If at the start of the journey one has no intention of stopping along the way for the purpose of staying over, and then something occurs which causes him to change his mind and make a layover, but then again he switches back to his original plan and continues on his journey ( without making an actual stop) , he does not have to say Tefilas Haderech a second time since his original intention was to continue.
25. Similarly if one says Tefilas Haderech intending to stop at a certain location and decide at that point whether to make a layover or a temporary rest stop, if he then decides to continue his journey, he does not have to repeat Tefilas Haderech on this leg of his trip.
A wealthy individual who was very hospitable, always giving the guests the best of food and drink, suffered a great loss when his house burned down. He came to the Vilna Gaon to try to understand why the merit of his hachnasas orchim — hospitality — was not sufficient to protect him from this great loss.
The Vilna Gaon explained to him that there are three aspects to hachnasas orchim which are alluded to in the acronym of the word aishel. Aishel stands for “achilah” — eating — “shetiyah” — drinking — and “leviyah” — escorting. Since his hachnasas orchim consisted of only attending to the guests’ first two needs without providing the required escort when leaving, his mitzvah was not sufficient to protect him from loss.