you never miss the water till the well runs dry

/juː nˈɛvə mˈɪs ðə wˈɔːtə tˈɪl ðə wˈɛl ɹˈʌnz dɹˈaɪ/

/juː nˈɛvɚ mˈɪs ðə wˈɔːɾɚ tˈɪl ðə wˈɛl ɹˈʌnz dɹˈaɪ/

used for imply that people often fail to appreciate the value of something or someone until they are no longer available or accessible