You might remember the meaning of the character 再 with this easy mnemonic:
It was a (一) moving experience to reunite with old primary school classmates again to dig out a time capsule from the earth (土). Had it not been for the worn down box (冂) placed as a marker, finding the location would had been difficult.
Using mnemonics to remember the meaning of Chinese characters like has a huge impact on how long to learn Mandarin it takes.