This useful amulet also exists in
ADOM, and has the same effect (it
resurrects anyone who dies while wearing it). However, amulets of life saving are much rarer in ADOM than in Nethack, and also much easier to lose. In Nethack, once you are wearing an
AoLS, the only way you are likely to lose it (other than dying) is if a
nymph steals it. In ADOM, it is vulnerable to being destroyed by
traps, like any other non-artifact item.
In Nethack, it's not generally considered worth wishing for an AoLS, because there are many other things (like gray dragon scale mail) which are more important. In ADOM, an AoLS is necessary to save Khelavaster, the dying sage, from certain death, which is compulsory if you're trying to become an Avatar of Order or Balance or an Ultimate Chaos God, and useful even if you're not, because you'll get a nice reward. It is therefore a good idea to wish for one and not wear it but leave it somewhere safe until you're ready to give it to Khelavaster.