1. It's easy to let yourself go when you are single.2. It's easy to let yourself go when you are out with your small kids.3. He used to have a sloppy appearance. After several failed attempts to ask a girl out, he finally learned his lesson and cleaned up his appearance.4. The artist has a bohemian appearance and spends all his time painting.
 let yourself go not care how one looks sloppy appearance untidy appearance a bohemian appearancelet yourself go = 不修邊幅，例如一個母親跟她的小孩出門，通常都會不修邊幅sloppy 很貼切，untidy 指不大整潔的外表，bohemian 是藝術家氣質的外表，也可說不修邊幅，並不會不整潔。
他之前往往不修邊幅, 後來經過多次跟女生約會失敗後總算學到教訓, 開始整理自己的儀容了
When the police found my lost kid I felt so relieve.