Answer
It depends on one’s level of consciousness. A brahmana, for example, may not think about tomorrow at all. But if one has not yet reached that level of consciousness, then thinking about keeping something for the future can also come under regulated self-preservation.
The four basic activities of material life are eating, sleeping, mating, and defending. Defending includes making reasonable arrangements for the future. Therefore, a grihastha may keep some savings or make practical arrangements for family responsibilities.
Srila Prabhupada explains that grihasthas are allowed to think about the future to some extent, but a sannyasi or brahmachari should not cultivate the mentality of worrying about tomorrow. Their opulence lies in depending fully on Krishna.
A devotee should not obsessively chase future security or constantly worry about it. Rather, one should make reasonable arrangements and then depend on Krishna. When you genuinely offer your life to Krishna, your self-preservation is never in danger, because Krishna takes care of His devotee.
