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

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

আপনি 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 পরবর্তি best thing.

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

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