What's 你 never know how much 你 cherished something until its gone mean?

It just means 你 didn't know what 你 had until 你 didn't have it any more, 你 didnt' see it while 你 had it, but once 你 didn't have it any 更多 你 realized what 你 missed... So I guess it also means appreciate what 你 have now cuz it could be gone tomorrow. :]

你 have to keep 2 things in mind:
1. We want what we can't/don't have.
2. We get easily bored and want the 下一个 best thing.

When 你 say that 你 don't know how much 你 cherished something until it's gone, 你 mean that when 你 own it 你 do not fully appreciate just how great it is until 你 no longer have it.

It might 或者 might not mean that they cherish something more. It all depends on the context of the situation and just how fickle that person is.