Mutable vs Inmutable

Hi... newbee here

I'm learning perl and also a little of LUA.

LUA has inmutable strings and Perl mutable strings.

¿What are the advantages/disadvantages of mutability?

ITS ALL BOUT THE CACEH LOCALITY OF THE L1 CACHE THAT MAKES UR COMPUTERS SPEED UP U SHUOLD USE IMNUTABLE STIRNGS BCUZ THEY HAV A BETTR ACEHC LOCALTIY BCUZ MUTABLE STRINGS  MAY GET MUTATED AND THAT MEANS U HAVE A CACHE MISS FOR EACH MUTATION YOU DO
DONT USE MTABLE STRINGS