Even when one takes a relaxed walk, he may not walk to his fields or factory in order to plan out his workweek. Doing so is included in the category of “your affairs,” which may not be addressed on Shabbat, as it is stated: “if you honor it, and not go in your own way, nor look to your affairs” (Yeshayahu 58:13). However, if it is not obvious that his intention is to plan his work, there is no prohibition. Therefore, one may take a Shabbat walk as long as onlookers cannot tell that he is looking over his fields. It is pious to avoid thinking about business on Shabbat altogether (see SA 306:8).
Similarly, one who is building a house should not check the progress on Shabbat, because it is obvious that he is planning his work, and one who intends to renovate or expand his home may not examine other projects if it is clear that he is planning the renovations. So too, one considering buying an apartment may not check out apartments for sale on Shabbat. In contrast, one considering buying an apartment may walk to a street where new apartments are being built even though his intention is to look them over, as long as it looks like he is just out for a walk and he does not stop and scrutinize them; this way, he does not look like he is planning his purchase. If one is planning to buy an electrical appliance, he may window-shop at appliance stores while walking on the street. However, he should not look at prices (SSK 29:10). In addition, it is pious to avoid thinking about these matters at all on Shabbat.
Toward the end of Shabbat, one may not walk to the edge of the teĥum in order to hire workers as soon after Shabbat as possible. Similarly, one may not go to his field, store, or factory at that time so that he can begin work immediately after Shabbat. Since it is clear that he is going there on Shabbat in order to work afterward, in effect he is dealing with his weekday affairs on Shabbat. However, if it is not clear that this is the reason he is going there, as is the case, for example, if many people take walks there, then he may walk there on Shabbat even if he intends to hire workers or begin his work immediately afterward. This is because the prohibition only applies when it is clear that he is going for a mundane purpose (SA 306:1; MB ad loc. 1; BHL s.v. “she-me’ayen; SA 307:9; MB ad loc. 40).