fix the roof while the sun is shining

From the notion that it is easier and more beneficial to fix a roof during dry rather than wet weather.

fix the roof while the sun is shining (third-person singular simple present fixes the roof while the sun is shining, present participle fixing the roof while the sun is shining, simple past and past participle fixed the roof while the sun was shining)

1. (proverbial) To deal with a problem or potential problem while conditions are favorable.
   • 1986, The Economist - Volume 299 - Page 4‎:

     You state it well: we should fix the roof while the sun is shining, and expand our nuclear-electric generating capacity while interest rates are low