Readings & Meanings:
In order to get money, the robber ordered "Your money or your life!" at knifepoint.
Tomorrow is the anniversary of your grandfather's death.
A turtle's lifespan is exceedingly long.
The father named the child "Katsu".
命 has the same widespread cover as 今 and 会 and all those. It also has a 口 radical. Plus, it looks suspiciously like 令, which means order, dictum (see 命令).
So 命 is a place to gather and be told what to do? I'd prefer to look at it as my kanjinetworks.com site describes it: your life (命) is your calling (mouth 口 + 令 order from a deity).
When I was in Ishikawa-ken on one of the most relaxing, pleasant beaches I've ever been to, a group of three Japanese guys came up to me. They noticed I was (a) a foreigner and (b) taking pictures, so the leader, in his Abercrombie shirt and sort-of sideways cap, started talking to me in little bits of English.
They eventually asked if I wanted to take their picture. I said sure, though I hadn't really been planning on it. They thought about what pose they should make, and then the leader said "いんち!" and made this pose.
They were imitating a Japanese comedian, who was himself imitating the kanji of 命. The arms are the cover, the legs are 口 and the other bit.
I'll never forget 命 because of these three 元気 guys.