What would you do if you won the lottery? Avraham returned from Egypt a fabulously wealthy man. One might have expected Avraham to use his newfound wealth for better accommodations or more comfortable and luxurious travel conditions. But he chose differently, living the life of humble simplicity that he lived before earning his fortune in Egypt. He decided to use the money for more important causes, such as hospitality.
Towards the beginning of Parashat Lekh-Lekha we read of Avraham's relocation in Egypt after Canaan is struck by drought, and the travails he experiences during this period. He ultimately emerges from Egypt as a wealthy man, and returns to Canaan. The verse states in describing his return, "Va-yeilekh le-masa'av," which literally means, "He went along his travels" (13:3). Rashi, however, citing the Midrash (Bereishit Rabba 41:3), explains this as a reference to Avraham's lodging as he made his way from Egypt to Canaan. He made a point of staying in the same inns where he had lodged as he traveled initially from Canaan to Egypt. "He went along his travels" thus means that he ensured to follow the same route as he did "along his travels" when he first moved to Egypt, and even stayed overnight at the same motels. Rashi refers us to the Gemara in Masekhet Arakhin (16b), which extracts from this verse a general rule that one should not lodge with a different host than the one with whom he had previous stayed. Seeking accommodations elsewhere raises suspicions about both the host and oneself, as people will conclude that either the host did not extend proper hospitality, or that he found the guest distasteful and did not invite him back.
Rav Avraham Pam (as cited in Rav Pam on Chumash) added yet another lesson that may be derived from Avraham's lodging as he returned to Canaan. Avraham had fled Canaan due to the financial hardships wrought by the drought, and returned from Egypt a fabulously wealthy man. This kind of drastic increase in wealth is generally followed by a drastic "upgrade" in one's quality of life. One might have expected Avraham to use his newfound wealth for better accommodations, to treat himself to more comfortable and luxurious travel conditions. But he chose differently, preferring to continue living the life of humble simplicity that he lived before earning his fortune in Egypt. He decided to use the money for more important causes, such as hospitality, of which we read in Parashat Vayera. Additionally, nobody really knows when or how the tides will reverse, and Avraham therefore exercised discretion in spending his fortune. This Midrash thus advises against squandering wealth on unnecessary luxury items, that even the wealthy should budget carefully and spend their money wisely.