prevent minor issues from becoming major problems； nip in the bud； take precautions against small problems to avoid big ones； stop trouble before it starts； forestall problems at an early stage

provident； contingency； take precautions； keep for a rainy day； be prepared for a rainy day； save for a rainy day； save against a rainy day； repair the house before it rains； provide for a rainy day； battens down the hatches； have an anchor to windward； don't have thy cloak to make when it begins to rain