I have not claimed rewards for the boxed I found and other people have opened.
I will wait until 2nd half of this event starts because I will have more slayers and slayer bonus in 2nd half.
The stamina restore items I have not claim dont start to rot until they are claimed.
Likewice I have not used and keys in first half after I got the SR.
Maybe I get benift from dont using keys in first half maybe not but it do me no harm.