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It's wise to save money for unlikely emergencies.
Literal
By-chance's time [for-に備えて] savings [object-を] do thing [topic-は] wise [copula-だ].
万一の時 ('the time of an unlikely event') with に備えて ('in preparation for') sets up a forward-looking contingency frame — a staple of life-advice and financial-planning prose. Using 貯金をする (with explicit を) rather than the compact 貯金する slightly emphasizes the act of saving as a deliberate ongoing practice. 賢明だ ('wise') closes with a moralistic verdict.